Systems and methods for controlling exhaust gas aftertreatment sensor systems

ABSTRACT

An exhaust gas aftertreatment system includes: a first sensor configured to measure a parameter in the exhaust gas aftertreatment system; a second sensor configured to measure the parameter in the exhaust gas aftertreatment system, the second sensor disposed proximate the first sensor; and at least one controller configured to simultaneously receive sensor values from the first sensor and receive sensor values from the second sensor.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 17/002,368, filed Aug. 25, 2020, which claims thebenefit of U.S. Provisional Application No. 62/893,545, filed Aug. 29,2019, the entire contents of these applications are incorporated hereinby reference.

TECHNICAL FIELD

The present application relates generally to the field of aftertreatmentsystems for internal combustion engines.

BACKGROUND

For internal combustion engines, such as diesel engines, nitrogen oxide(NO_(x)) compounds may be emitted in exhaust. To reduce NO_(x)emissions, a selective catalytic reduction (SCR) process may beimplemented to convert the NO_(x) compounds into more neutral compounds,such as diatomic nitrogen, water, or carbon dioxide, with the aid of acatalyst and a liquid reductant. The catalyst may be included in acatalyst chamber of an exhaust system, such as that of a vehicle orpower generation unit. A liquid reductant, such as anhydrous ammonia,aqueous ammonia, diesel exhaust fluid (DEF), or aqueous urea, istypically introduced into the exhaust gas flow prior to the catalystchamber.

In some applications, failure of sensors to detect various constituentscan reduce the efficacy of the exhaust gas aftertreatment system andnegatively impact overall system performance.

SUMMARY

Embodiments described herein relate generally to systems and methods forcontrolling exhaust gas aftertreatment sensor systems.

In one embodiment, an exhaust gas aftertreatment system includes a firstsensor configured to measure a parameter in the exhaust gasaftertreatment system; a second sensor configured to measure theparameter in the exhaust gas aftertreatment system, the second sensordisposed proximate the first sensor; and at least one controllerconfigured to: initially, utilize the first sensor as a primary sensorfor measuring the parameter in the exhaust gas aftertreatment system; attarget intervals: receive a first sensor value from the first sensor,receive a second sensor value from the second sensor, calculate adifference between the first sensor value and the second sensor value,and determine if the difference between the first sensor value and thesecond sensor value is greater than a threshold value; and if thedifference between the first sensor value and the second sensor value isgreater than the threshold value, stop utilizing the first sensor as theprimary sensor for measuring the parameter in the exhaust gasaftertreatment system, and begin utilizing the second sensor as theprimary sensor for measuring the parameter in the exhaust gasaftertreatment system.

In another embodiment, an exhaust gas aftertreatment system includes afirst sensor configured to measure a parameter in the exhaust gasaftertreatment system; a second sensor configured to measure theparameter in the exhaust gas aftertreatment system, the second sensordisposed proximate the first sensor; and at least one controllerconfigured to alternately receive sensor values from the first sensorfor a first target period of time, and receive sensor values from thesecond sensor for a second target period of time.

In another embodiment, an exhaust gas aftertreatment system includes afirst sensor configured to measure a parameter in the exhaust gasaftertreatment system; a second sensor configured to measure theparameter in the exhaust gas aftertreatment system, the second sensordisposed proximate the first sensor; and at least one controllerconfigured to: simultaneously receive sensor values from the firstsensor and receive sensor values from the second sensor.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features,aspects, and advantages of the disclosure will become apparent from thedescription, the drawings, and the claims, in which:

FIG. 1 illustrates a block schematic diagram of an example exhaust gasaftertreatment system having an example reductant delivery system andexample exhaust gas aftertreatment sensor system, according to anembodiment.

FIG. 2 illustrates a cross-sectional view of the exhaust gasaftertreatment system shown in FIG. 1, taken along plane A-A, plane B-B,plane C-C, or plane D-D, according to an embodiment.

FIG. 3 illustrates a cross-sectional view of the exhaust gasaftertreatment system shown in FIG. 1, taken along plane A-A, plane B-B,plane C-C, or plane D-D, according to an embodiment.

FIG. 4 illustrates a block schematic diagram of an example exhaust gasaftertreatment system having an example reductant delivery system andexample exhaust gas aftertreatment sensor system, according to anembodiment.

FIG. 5 illustrates a diagram of an example sensor for an exhaust gasaftertreatment sensor system, according to an embodiment.

FIG. 6A illustrates a diagram of an example sensor with a single sensingelement for an exhaust gas aftertreatment sensor system, according to anembodiment. FIG. 6B illustrates a diagram of an example sensor withmultiple sensing elements for an exhaust gas aftertreatment sensorsystem, according to an embodiment.

FIG. 7 is a flow chart of an example serial process implemented by anexhaust gas aftertreatment sensor system, according to an embodiment.

FIG. 8 is a flow chart of an example alternating selection processimplemented by an exhaust gas aftertreatment sensor system, according toan embodiment.

FIG. 9 is a flow chart of an example simultaneous selection processimplemented by an exhaust gas aftertreatment sensor system, according toan embodiment.

It will be recognized that some or all of the Figures are schematicrepresentations for purposes of illustration. The Figures are providedfor the purpose of illustrating one or more implementations with theexplicit understanding that they will not be used to limit the scope orthe meaning of the claims.

DETAILED DESCRIPTION

Following below are more detailed descriptions of various conceptsrelated to, and implementations of, methods, apparatuses, and systemsfor controlling exhaust gas aftertreatment sensor systems. The variousconcepts introduced above and discussed in greater detail below may beimplemented in any of numerous ways, as the described concepts are notlimited to any particular manner of implementation. Examples of specificimplementations and applications are provided primarily for illustrativepurposes.

I. Overview

Internal combustion engines (e.g., diesel internal combustion engines,etc.) produce exhaust gas that is often treated within an exhaust gasaftertreatment system. This treatment often includes treating (e.g.,dosing, etc.) the exhaust gas with a reductant and subsequently passingthe exhaust gas through an SCR catalyst to convert NO_(x) emissions intomore neutral compounds. Sensors can be located in the exhaust gasaftertreatment system to detect the presence of, and/or amounts (e.g.,levels, etc.) of, specific compounds (e.g., constituents, etc.). Forexample, sensors of an exhaust gas aftertreatment sensor system can beused by an exhaust gas aftertreatment system to determine a particulatecount of specific constituents. Failure of these sensors can reduce theefficacy of the exhaust gas aftertreatment system and negatively impactoverall system performance. Additionally, failure of these sensors canresult in significant vehicle downtime and expensive diagnostic andrepair cost.

According to one embodiment, the exhaust gas aftertreatment sensorsystem can operate in a serial process. The exhaust gas aftertreatmentsensor system includes a first sensor that is configured to measure aparameter of the exhaust gas flowing through the exhaust gasaftertreatment system. The parameter of the exhaust gas flowing throughthe exhaust gas aftertreatment system corresponds to at least one of aconcentration of gases, pressure difference, particulate matter, orparticulate number. The exhaust gas aftertreatment sensor system alsoincludes a second sensor that is configured to measure the parameter(e.g., the same parameter measured by the first sensor) of the exhaustgas flowing through the exhaust gas aftertreatment system. The secondsensor is disposed proximate the first sensor. The exhaust gasaftertreatment sensor system can include additional sensors (e.g., athird sensor, a fourth sensor, a fifth sensor, etc.) that all measurethe same parameter of the exhaust gas flowing through the exhaust gasaftertreatment system. The exhaust gas aftertreatment sensor system alsoincludes a controller. The controller is configured to initially utilizethe first sensor as a primary sensor for measuring the parameter of theexhaust gas. While the first sensor is used as the primary sensor, thesecond sensor is used as a secondary sensor and the controller does notutilize measurements from the second sensor. If the first sensor shouldfail, the controller is configured to utilize the second sensor as theprimary sensor for measuring the parameter (e.g., upon detection of thefailure of the first sensor, etc.) and utilize the first sensor as thesecondary sensor, with the controller not utilizing measurements fromthe first sensor.

According to another embodiment, the exhaust gas aftertreatment sensorsystem can operate in an alternating selection process. In thealternating selection process, the controller is configured toalternately receive sensor values from a first sensor for a first targetperiod of time, and receive sensor values from a second sensor for asecond target period of time. Sensor values correspond to the parameterof the exhaust gas flowing through the exhaust gas aftertreatmentsystem. For example, sensor values are voltage values that thecontroller receives from the sensors. In this embodiment, thealternating between the first sensor and the second sensor occurs basedupon time, and does not depend upon detection of failure of the firstsensor or the second sensor.

According to another embodiment, the exhaust gas aftertreatment sensorsystem can operate in a simultaneous selection process. In thesimultaneous selection process, the controller is configured tosimultaneously receive sensor values from the first sensor and receivesensor values from the second sensor.

The exhaust gas aftertreatment sensor system described herein may haveincreased robustness and therefore an extended overall lifetime comparedto other sensing systems. By extending the overall lifetime, a costassociated with an exhaust gas aftertreatment system using the exhaustgas aftertreatment sensor system can be decreased compared toaftertreatment systems which use other sensing systems because theexhaust gas aftertreatment system sensor system can remain functionalfor a longer period of time. Additionally, the exhaust gasaftertreatment sensor system described herein may have increasedaccuracy compared to other sensing systems because a functionality andaccuracy of the exhaust gas aftertreatment sensor system is periodicallyconfirmed. Other sensing systems lack any mechanism for performingperiodic accuracy and functionality checks and therefore are prone tobecoming inaccurate and/or non-functional at unpredictable, andpotentially undesirable, times. By periodically confirming functionalityand accuracy, the exhaust gas aftertreatment sensor system describedherein may reduce a frequency and number of service events required byother sensing systems because functionality and accuracy are confirmedat times other than during service events.

II. Overview of a First Vehicle System

FIG. 1 illustrates an example vehicle system 100. The vehicle system 100includes an exhaust gas aftertreatment system 102 having a reductantdelivery system 104 for an exhaust gas conduit system 106. The vehiclesystem 100 also includes an internal combustion engine 108 (e.g., dieselinternal combustion engine, diesel hybrid internal combustion engine,gasoline internal combustion engine, natural gas internal combustionengine, liquid propane internal combustion engine, etc.) which producesexhaust gas that is received by the exhaust gas aftertreatment system102. The internal combustion engine 108 receives fuel (e.g., dieselfuel, gasoline, natural gas, liquid propane, etc.) from a fuel tank 110(e.g., reservoir, etc.). The fuel tank 110 is configured to bereplenished (e.g., by a user, etc.).

The exhaust gas aftertreatment system 102 also includes an oxidationcatalyst 111 (e.g., a diesel oxidation catalyst (DOC), etc.). Theoxidation catalyst 111 is configured to (e.g., structured to, able to,etc.) promote oxidation of hydrocarbons and/or carbon monoxide inexhaust gas produced by the internal combustion engine 108 and flowingin the exhaust gas conduit system 106. In some implementations, theoxidation catalyst 111 may be omitted.

The exhaust gas aftertreatment system 102 also includes a particulatefilter 112 (e.g., a diesel particulate filter (DPF), a gasolineparticulate filter (GPF), etc.). The particulate filter 112 isconfigured to remove particulate matter, such as soot, from the exhaustgas provided by the oxidation catalyst 111. The particulate filter 112includes an inlet, where the exhaust gas is received, and an outlet,where the exhaust gas exits after having particulate mattersubstantially filtered from the exhaust gas and/or converting theparticulate matter into carbon dioxide. In some implementations, theparticulate filter 112 may be omitted.

The exhaust gas aftertreatment system 102 also includes a decompositionchamber 114 (e.g., reactor, reactor pipe, compact mixer, mixer, etc.).The decomposition chamber 114 is configured to convert a reductant intoammonia. The reductant may be, for example, urea, diesel exhaust fluid(DEF), Adblue®, a urea water solution (UWS), an aqueous urea solution(AUS) (e.g., AUS32, etc.), and other similar fluids. The decompositionchamber 114 includes an inlet in fluid communication with theparticulate filter 112 to receive the exhaust gas containing NO_(x)emissions and an outlet for the exhaust gas, NO_(x) emissions, ammonia,and/or reductant to flow from the decomposition chamber 114.

The exhaust gas aftertreatment system 102 also includes a conversioncatalyst 116 (e.g., a selective catalytic reduction (SCR) catalyst, acopper-zeolite SCR catalyst, etc.). The conversion catalyst 116 isconfigured to assist in the reduction of NO_(x) emissions byaccelerating a NO_(x) reduction process between the ammonia and theNO_(x) of the exhaust gas into diatomic nitrogen, water, and/or carbondioxide. The conversion catalyst 116 includes an inlet in fluidcommunication with the decomposition chamber 114 from which exhaust gasand reductant are received and an outlet in fluid communication with anend of the exhaust gas conduit system 106.

The decomposition chamber 114 is located upstream of the conversioncatalyst 116. As a result, the reductant is injected upstream of theconversion catalyst 116 such that the conversion catalyst 116 receives amixture of the reductant and exhaust gas. The reductant droplets undergothe processes of evaporation, thermolysis, and hydrolysis to formnon-NO_(x) emissions (e.g., gaseous ammonia, etc.) within the exhaustgas conduit system 106.

The exhaust gas aftertreatment system 102 also includes an ammonia slipcatalyst (ASC) 117. The ammonia slip catalyst 117 is configured toassist in the conversion of ammonia (NH₃) into diatomic nitrogen. Theammonia slip catalyst 117 is located downstream of the conversioncatalyst 116.

The reductant delivery system 104 includes a dosing module 118 (e.g.,doser, etc.) configured to dose the reductant into the decompositionchamber 114 (e.g., via an injector, etc.). The dosing module 118 ismounted to the decomposition chamber 114 such that the dosing module 118may dose the reductant into the exhaust gas flowing in the exhaust gasconduit system 106. The dosing module 118 may include an insulator(e.g., thermal insulator, etc.) and/or isolator (e.g., vibrationalisolator, etc.) interposed between a portion of the dosing module 118and the portion of the decomposition chamber 114 on which the dosingmodule 118 is mounted.

The dosing module 118 is fluidly coupled to (e.g., fluidly configured tocommunicate with, etc.) a reductant source 120 (e.g., reductant tank,reductant reservoir, etc.). The reductant source 120 may includemultiple reductant sources 120. The reductant source 120 may be, forexample, a DEF tank containing Adblue®. A reductant pump 121 (e.g.,supply unit, etc.) is used to pressurize the reductant from thereductant source 120 for delivery to the dosing module 118. In someembodiments, the reductant pump 121 is pressure controlled (e.g.,controlled to obtain a target pressure, etc.). The reductant pump 121may draw the reductant through a reductant filter 122. The reductantfilter 122 filters (e.g., strains, etc.) the reductant prior to thereductant being provided to internal components (e.g., pistons, vanes,etc.) of the reductant pump 121. For example, the reductant filter 122may inhibit or prevent the transmission of solids (e.g., solidifiedreductant, contaminants, etc.) to the internal components of thereductant pump 121. In this way, the reductant filter 122 may facilitateprolonged desirable operation of the reductant pump 121. In someembodiments, the reductant pump 121 is coupled to a chassis of a vehicleassociated with the exhaust gas aftertreatment system 102.

The dosing module 118 includes at least one injector 124 (e.g.,reductant injector, etc.). Each injector 124 is configured to dose thereductant into the exhaust gas (e.g., within the decomposition chamber114, etc.). The injector 124 may be positioned to cause the reductant toachieve a target uniformity index (UI) within the exhaust gas at atarget location (e.g., at an inlet of the conversion catalyst 116,etc.).

In some embodiments, the reductant delivery system 104 also includes anair pump 126. In these embodiments, the air pump 126 draws air from anair source 128 (e.g., air intake, atmosphere, etc.) and through an airfilter 130 disposed upstream of the air pump 126. The air filter 130filters the air prior to the air being provided to internal components(e.g., pistons, vanes, etc.) of the air pump 126. For example, the airfilter 130 may inhibit or prevent the transmission of solids (e.g.,debris, branches, dirt, etc.) to the internal components of the air pump126. In this way, the air filter 130 may facilitate prolonged desirableoperation of the air pump 126. The air pump 126 provides the air to thedosing module 118 via a conduit. The dosing module 118 is configured tomix the air and the reductant into an air-reductant mixture and toprovide the air-reductant mixture into the decomposition chamber 114. Inother embodiments, the reductant delivery system 104 does not includethe air pump 126, the air source 128, or the air filter 130. In suchembodiments, the dosing module 118 is not configured to mix thereductant with air.

The dosing module 118 and the reductant pump 121 are also electricallyor communicatively coupled to an exhaust gas aftertreatment systemcontroller 132. The exhaust gas aftertreatment system controller 132 isconfigured to control the dosing module 118 to dose the reductant intothe decomposition chamber 114. The exhaust gas aftertreatment systemcontroller 132 may also be configured to control the reductant pump 121.

The exhaust gas aftertreatment system controller 132 includes aprocessing circuit 134. The processing circuit 134 includes a processor136 and a memory 138. The processor 136 may include a microprocessor, anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA), etc., or combinations thereof. The memory 138 mayinclude, but is not limited to, electronic, optical, magnetic, or anyother storage or transmission device capable of providing a processor,ASIC, FPGA, etc. with program instructions. This memory 138 may includea memory chip, Electrically Erasable Programmable Read-Only Memory(EEPROM), Erasable Programmable Read Only Memory (EPROM), flash memory,or any other suitable memory from which the exhaust gas aftertreatmentsystem controller 132 can read instructions. The instructions mayinclude code from any suitable programming language. The memory 138 mayinclude various modules that include instructions which are configuredto be implemented by the processor 136.

While not shown, it is understood that the internal combustion engine108 includes various components, such as cylinders, pistons, fuelinjectors, air intakes, and other similar components. In someapplications, the internal combustion engine 108 may include aturbocharger, an exhaust gas recirculation (EGR) system, a waste heatrecovery (WHR) system, a cylinder cutout system, and/or other similarcomponents.

In some implementations, the particulate filter 112 may be positioneddownstream of the decomposition chamber 114. For instance, theparticulate filter 112 and the conversion catalyst 116 may be combinedinto a single unit. In some implementations, the dosing module 118 mayinstead be positioned downstream of a turbocharger or upstream of aturbocharger. There may, in some implementations, be more than one SCRcatalyst.

III. Overview of a First Exhaust Gas Aftertreatment Sensor System

The vehicle system 100 also includes a first exhaust gas aftertreatmentsensor system 157 (e.g., sensing system, sensing assembly, sensorarrangement, accessory sensing system, accessory sensor system, etc.).The first exhaust gas aftertreatment sensor system 157 includes a firstengine-out NO_(x) sensor 150 a (e.g., sensing unit, sensing module,sensing component, sensor unit, sensor unit, sensor component, etc.).The first engine-out NO_(x) sensor 150 a is located upstream of theoxidation catalyst 111 and downstream of the internal combustion engine108. The first exhaust gas aftertreatment sensor system 157 alsoincludes a second engine-out NO_(x) sensor 150 b (e.g., sensing unit,sensing module, sensing component, sensor unit, sensor unit, sensorcomponent, etc.). The second engine-out NO_(x) sensor 150 b is alsolocated upstream of the oxidation catalyst 111 and downstream of theinternal combustion engine 108. The second engine-out NO_(x) sensor 150b may be located upstream of the first engine-out NO_(x) sensor 150 a,downstream of the first engine-out NO_(x) sensor 150 a, or parallel withthe first engine-out NO_(x) sensor 150 a. The first exhaust gasaftertreatment sensor system 157 also includes a third engine-out NO_(x)sensor 150 c (e.g., sensing unit, sensing module, sensing component,sensor unit, sensor unit, sensor component, etc.). The third engine-outNO_(x) sensor 150 c is located upstream of the oxidation catalyst 111and downstream of the internal combustion engine 108. The thirdengine-out NO_(x) sensor 150 c may be located upstream of the firstengine-out NO_(x) sensor 150 a, downstream of the first engine-outNO_(x) sensor 150 a, or parallel with the first engine-out NO_(x) sensor150 a and upstream of the second engine-out NO_(x) sensor 150 b,downstream of the second engine-out NO_(x) sensor 150 b, or parallelwith the second engine-out NO_(x) sensor 150 b.

The first engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, and the third engine-out NO_(x) sensor 150 c are eachconfigured to independently determine a NO_(x) concentration of theexhaust gas exiting the internal combustion engine 108. The exhaust gasaftertreatment system controller 132 is configured to use these NO_(x)concentrations to, for example, control the dosing module 118 to dosethe reductant into the decomposition chamber 114.

The first engine-out NO_(x) sensor 150 a can include an engine-outNO_(x) filter 151. The engine-out NO_(x) filter 151 can inhibit orprevent intrusion of particulate matter and/or liquid water dropletsinto any of the first engine-out NO_(x) sensor 150 a, the secondengine-out NO_(x) sensor 150 b, or the third engine-out NO_(x) sensor150 c while facilitating diffusion and flow of exhaust gas moleculesinto any of the first engine-out NO_(x) sensor 150 a, the secondengine-out NO_(x) sensor 150 b, or the third engine-out NO_(x) sensor150 c. The engine-out NO_(x) filter 151 can include a filter screen. Thesecond engine-out NO_(x) sensor 150 b can include the engine-out NO_(x)filter 151. The third engine-out NO_(x) sensor 150 c can include theengine-out NO_(x) filter 151. The engine-out NO_(x) filter 151 may ormay not be included with any of the first engine-out NO_(x) sensor 150a, the second engine-out NO_(x) sensor 150 b, or the third engine-outNO_(x) sensor 150 c.

The first exhaust gas aftertreatment sensor system 157 also includes afirst particulate sensor 160 a (e.g., particulate matter sensor,particulate number sensor, etc.). The first particulate sensor 160 a islocated upstream of the conversion catalyst 116 (e.g., upstream of thedecomposition chamber 114, within the decomposition chamber 114, etc.)and downstream of the particulate filter 112. The first exhaust gasaftertreatment sensor system 157 also includes a second particulatesensor 160 b (e.g., particulate matter sensor, particulate numbersensor, etc.). The second particulate sensor 160 b is located upstreamof the conversion catalyst 116 (e.g., upstream of the decompositionchamber 114, within the decomposition chamber 114, etc.) and downstreamof the particulate filter 112. The first exhaust gas aftertreatmentsensor system 157 also includes a third particulate sensor 160 c (e.g.,particulate matter sensor, particulate number sensor, etc.). The thirdparticulate sensor 160 c is located upstream of the conversion catalyst116 (e.g., upstream of the decomposition chamber 114, within thedecomposition chamber 114, etc.) and downstream of the particulatefilter 112.

The first particulate sensor 160 a, the second particulate sensor 160 b,and the third particulate sensor 160 c are each configured toindependently determine an amount of particulate matter within theexhaust gas downstream of the particulate filter 112 and upstream of theconversion catalyst 116. The exhaust gas aftertreatment systemcontroller 132 is configured to use these amounts of particulate matterto, for example, determine if a diesel particulate filter 112 isfunctioning as intended or requires service. For the first particulatesensor 160 a, the second particulate sensor 160 b, or the thirdparticulate sensor 160 c an isokinetic sampling probe can be used toensure representative sampling and minimal particle loss due to gasvelocity gradients near the sampling probe.

The first exhaust gas aftertreatment sensor system 157 also includes afirst NH₃ sensor 162 a (e.g., sensing unit, sensing module, sensingcomponent, sensor unit, sensor unit, sensor component, etc.). The firstNH₃ sensor 162 a is located upstream of the ammonia slip catalyst 117and downstream of the conversion catalyst 116. The first exhaust gasaftertreatment sensor system 157 also includes a second NH₃ sensor 162 b(e.g., sensing unit, sensing module, sensing component, sensor unit,sensor unit, sensor component, etc.). The second NH₃ sensor 162 b islocated upstream of the ammonia slip catalyst 117 and downstream of theconversion catalyst 116. The first exhaust gas aftertreatment sensorsystem 157 also includes a third NH₃ sensor 162 c (e.g., sensing unit,sensing module, sensing component, sensor unit, sensor unit, sensorcomponent, etc.). The third NH₃ sensor 162 c is located upstream of theammonia slip catalyst 117 and downstream of the conversion catalyst 116.In some embodiments, the first NH₃ sensor 162 a, second NH₃ sensor 162b, and third NH₃ sensor 162 c are located downstream of the ammonia slipcatalyst 117.

The first NH₃ sensor 162 a, the second NH₃ sensor 162 b, and the thirdNH₃ sensor 162 c are each configured to independently determine an NH₃concentration of the exhaust gas exiting the conversion catalyst 116.The exhaust gas aftertreatment system controller 132 is configured touse these NH₃ concentrations to, for example, control the dosing module118 to dose the reductant into the decomposition chamber 114.

The first NH₃ sensor 162 a can include a NH₃ filter 163. The NH₃ filter163 can inhibit or prevent intrusion of particulate matter and/or liquidwater droplets into any of the first NH₃ sensor 162 a, the second NH₃sensor 162 b, or the third NH₃ sensor 162 c while facilitating diffusionand flow of gas molecules into any of the first NH₃ sensor 162 a, thesecond NH₃ sensor 162 b, or the third NH₃ sensor 162 c. The NH₃ filter163 can include a filter screen. The second NH₃ sensor 162 b can includethe NH₃ filter 163. The third NH₃ sensor 162 c can include the NH₃filter 163. The NH₃ filter 163 may or may not be included with the firstNH₃ sensor 162 a, the second NH₃ sensor 162 b, or the third NH₃ sensor162 c.

The first exhaust gas aftertreatment sensor system 157 also includes afirst system-out NO_(x) sensor 164 a (e.g., sensing unit, sensingmodule, sensing component, sensor unit, sensor unit, sensor component,etc.). The first system-out NO_(x) sensor 164 a is located downstream ofthe ammonia slip catalyst 117. The first exhaust gas aftertreatmentsensor system 157 also includes a second system-out NO_(x) sensor 164 b(e.g., sensing unit, sensing module, sensing component, sensor unit,sensor unit, sensor component, etc.). The second system-out NO_(x)sensor 164 b is located downstream of the ammonia slip catalyst 117. Thefirst exhaust gas aftertreatment sensor system 157 also includes a thirdsystem-out NO_(x) sensor 164 c (e.g., sensing unit, sensing module,sensing component, sensor unit, sensor unit, sensor component, etc.).The third system-out NO_(x) sensor 164 c is located downstream of theammonia slip catalyst 117. The first system-out NO_(x) sensor 164 a, thesecond system-out NO_(x) sensor 164 b, and the third system-out NO_(x)sensor 164 c are each configured to independently determine NO_(x)concentrations of the exhaust gas exiting the exhaust gas aftertreatmentsystem 102 (e.g., downstream of the ammonia slip catalyst 117, etc.).The exhaust gas aftertreatment system controller 132 is configured touse these NO_(x) concentrations to, for example, control the dosingmodule 118 to dose the reductant into the decomposition chamber 114.

The first system-out NO_(x) sensor 164 a can include a system-out NO_(x)filter 165. The system-out NO_(x) filter 165 can inhibit or preventintrusion of particulate matter and/or liquid water droplets into any ofthe first system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, or the third system-out NO_(x) sensor 164 c whilefacilitating diffusion and flow of exhaust gas molecules into any of thefirst system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, or the third system-out NO_(x) sensor 164 c system-out.The system-out NO_(x) filter 165 can include a filter screen. The secondsystem-out NO_(x) sensor 164 b can include the system-out NO_(x) filter165. The third system-out NO_(x) sensor 164 c can include the system-outNO_(x) filter 165. The system-out NO_(x) filter 165 may or may not beincluded with any of the first system-out NO_(x) sensor 164 a, thesecond system-out NO_(x) sensor 164 b, or the third system-out NO_(x)sensor 164 c.

The first exhaust gas aftertreatment sensor system 157 also includes theexhaust gas aftertreatment system controller 132. The exhaust gasaftertreatment system controller 132 is configured to communicate withthe first engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, the third engine-out NO_(x) sensor 150 c, the firstparticulate sensor 160 a, the second particulate sensor 160 b, the thirdparticulate sensor 160 c, the first NH₃ sensor 162 a, the second NH₃sensor 162 b, the third NH₃ sensor 162 c, the first system-out NO_(x)sensor 164 a, the second system-out NO_(x) sensor 164 b, and/or thethird system-out NO_(x) sensor 164 c. The exhaust gas aftertreatmentsystem controller 132 can be implemented across several controllers. Forexample, a first exhaust gas aftertreatment system controller cancontrol the first engine-out NO_(x) sensor 150 a, the first particulatesensor 160 a, the first NH₃ sensor 162 a, and/or the first system-outNO_(x) sensor 164 a. A second exhaust gas aftertreatment systemcontroller can control the second engine-out NO_(x) sensor 150 b, thesecond particulate sensor 160 b, the second NH₃ sensor 162 b, and/or thesecond system-out NO_(x) sensor 164 b. A third exhaust gasaftertreatment system controller can control the third engine-out NO_(x)sensor 150 c, the third particulate sensor 160 c, the third NH₃ sensor162 c, and/or the third system-out NO_(x) sensor 164 c.

The memory 138 also includes a sensor determination module 153 (e.g.,circuit, etc.). The sensor determination module 153 determines, out of aset of sensors (e.g., a first set of sensors including the firstengine-out NO_(x) sensor 150 a, the second engine-out NO_(x) sensor 150b, and the third engine-out NO_(x) sensor 150 c, a second set of sensorsincluding the first particulate sensor 160 a, the second particulatesensor 160 b, and the third particulate sensor 160 c, a third set ofsensors including the first NH₃ sensor 162 a, the second NH₃ sensor 162b, and the third NH₃ sensor 162 c, a fourth set of sensors including thefirst system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, and the third system-out NO_(x) sensor 164 c, etc.), whichsensor (e.g., the first engine-out NO_(x) sensor 150 a, the secondengine-out NO_(x) sensor 150 b, the third engine-out NO_(x) sensor 150c, the first particulate sensor 160 a, the second particulate sensor 160b, the third particulate sensor 160 c, the first NH₃ sensor 162 a, thesecond NH₃ sensor 162 b, the third NH₃ sensor 162 c, the firstsystem-out NO_(x) sensor 164 a, the second system-out NO_(x) sensor 164b, the third system-out NO_(x) sensor 164 c) is the primary sensor. Forexample, the sensor determination module 153 can determine that of thefirst engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, and the third engine-out NO_(x) sensor 150 c, the firstengine-out NO_(x) sensor 150 a is the primary sensor. In anotherexample, the sensor determination module 153 can determine that of thefirst NH₃ sensor 162 a, the second NH₃ sensor 162 b, and the third NH₃sensor 162 c, the second NH₃ sensor 162 b is the primary sensor.

The memory 138 also includes a sensor operation module 155 (e.g.,circuit, etc.). The sensor operation module 155 is configured to receivesensor values. For example, the sensor operation module 155 can receivea first sensor value from the first engine-out NO_(x) sensor 150 a, thefirst particulate sensor 160 a, the first NH₃ sensor 162 a, and/or thefirst system-out NO_(x) sensor 164 a. The sensor operation module 155can receive a second sensor value from the second engine-out NO_(x)sensor 150 b, the second particulate sensor 160 b, the second NH₃ sensor162 b, and/or the second system-out NO_(x) sensor 164 b. The sensoroperation module 155 can receive a third sensor value from the thirdengine-out NO_(x) sensor 150 c, the third particulate sensor 160 c, thethird NH₃ sensor 162 c, and/or the third system-out NO_(x) sensor 164 c.

The memory 138 also includes a sensor value difference module 154 (e.g.,circuit, etc.). The sensor value difference module 154 stores adifference D₁₋₂ between a first sensor value and a second sensor value.The exhaust gas aftertreatment system controller 132 can compare theD₁₋₂ to a threshold value to determine if a sensor is failing or hasfailed. The sensor value difference module 154 also stores a differenceD₂₋₃ between a second sensor value and a third sensor value. The exhaustgas aftertreatment system controller 132 can compare the D₂₋₃ to athreshold value to determine if a sensor is failing or has failed. Thesensor value difference module 154 also stores a difference D_(1-C)between a first sensor value and a calculated sensor value (e.g.,virtual sensor value, tabulated sensor value, etc.). The exhaust gasaftertreatment system controller 132 can compare the D_(1-C) to athreshold value to determine if a sensor is failing or has failed. Thesensor value difference module 154 also stores a difference D_(2-C)between a second sensor value and a calculated sensor value. The exhaustgas aftertreatment system controller 132 can compare the D_(2-C) to athreshold value to determine if a sensor is failing or has failed. Thesensor value difference module 154 also stores a difference D_(3-C)between a third sensor value and a calculated sensor value. The exhaustgas aftertreatment system controller 132 can compare the D_(3-C) to athreshold value to determine if a sensor is failing or has failed. TheD₁₋₂ may be approximately equal to (e.g., within 5% of, etc.) 10 ppm, 5ppm, 15 ppm, 20 ppm, or other similar values. The D₂₋₃ may beapproximately equal to 10 ppm, 5 ppm, 15 ppm, 20 ppm, or other similarvalues. The D_(1-C) may be approximately equal to 10 ppm, 5 ppm, 15 ppm,20 ppm, or other similar values. The D_(2-C) may be approximately equalto 10 ppm, 5 ppm, 15 ppm, 20 ppm, or other similar values. The D_(3-C)may be approximately equal to 10 ppm, 5 ppm, 15 ppm, 20 ppm, or othersimilar values.

FIG. 2 illustrates a cross-sectional view of the exhaust gasaftertreatment system shown in FIG. 1, taken along plane A-A, plane B-B,plane C-C, or plane D-D, according to an embodiment. The first exhaustgas aftertreatment sensor system 157 includes a first sensor 202 (e.g.,sensing unit, sensing module, sensing component, sensor unit, sensorunit, sensor component, etc.) that is configured to measure a parameterin the exhaust gas aftertreatment system 102. The parameter in theexhaust gas aftertreatment system 102 can include a concentration of gas(e.g., NO_(x), NH₃, O₂, etc.), particulate matter, particulate number,or pressure. The first sensor 202 includes at least one of a multiplegas sensor, a particulate matter sensor, a particulate number sensor, ora delta pressure sensor. The first sensor 202 is at least one of thefirst engine-out NO_(x) sensor 150 a, the first particulate sensor 160a, the first NH₃ sensor 162 a, or the first system-out NO_(x) sensor 164a.

The first exhaust gas aftertreatment sensor system 157 includes a secondsensor 204 (e.g., sensing unit, sensing module, sensing component,sensor unit, sensor unit, sensor component, etc.) that is configured tomeasure the parameter in the exhaust gas aftertreatment system 102. Thesecond sensor 204 includes at least one of a multiple gas sensor, aparticulate matter sensor, a particulate number sensor, or a deltapressure sensor. The second sensor 204 is at least one of the secondengine-out NO_(x) sensor 150 b, the second particulate sensor 160 b, thesecond NH₃ sensor 162 b, or the second system-out NO_(x) sensor 164 b.The first sensor 202 and the second sensor 204 can each be one of theprimary sensor or the secondary sensor (e.g., the first sensor can bethe primary sensor and the second sensor can be the secondary sensor,the first sensor can be the secondary sensor and the second sensor canbe the primary sensor).

The second sensor 204 is disposed proximate the first sensor 202. Forexample, the second sensor 204 can be in close proximity to the firstsensor 202 such that the second sensor 204 and the first sensor 202 givesubstantially equal sensor values (e.g., readings, etc.). As shown inFIG. 2, the first sensor 202 and the second sensor 204 are located on aplane perpendicular to the flow of the exhaust gas in the exhaust gasaftertreatment system 102. The first sensor 202 is located a distance D₁from a center point C of an exhaust gas conduit 190 of the exhaust gasconduit system 106 as measured along a radius of the exhaust gas conduit190. The first sensor 202 is coupled to the exhaust gas conduit 190.Similarly, the second sensor 204 is located a distance D₂ from thecenter point C. The second sensor 204 is coupled to the exhaust gasconduit 190. The location of the first sensor 202 and the second sensor204 can enable the first exhaust gas aftertreatment sensor system 157 tomeasure the uniformity of the gas concentration. If the gasconcentration is non-uniform, a deposit removal or other diagnosticevent can be triggered. The first sensor 202 and the second sensor 204are separated by an angle α. In one embodiment, the angle α is 90degrees. However, in various applications the angles may besubstantially equal to (e.g., within 5% of, etc.) 40 degrees, 50degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees 100 degrees, 110degrees, 120 degrees, 130 degrees, or other similar values.

In some embodiments, the first exhaust gas aftertreatment sensor system157 only has the first sensor 202 and the second sensor 204 downstreamof the internal combustion engine 108 and upstream of the oxidationcatalyst 111. In some embodiments, the first exhaust gas aftertreatmentsensor system 157 only has the first sensor 202 and the second sensor204 upstream of the conversion catalyst 116 and downstream of theparticulate filter 112. In some embodiments, the first exhaust gasaftertreatment sensor system 157 only has the first sensor 202 and thesecond sensor 204 upstream of the ammonia slip catalyst 117 anddownstream of the conversion catalyst 116. In some embodiments, thefirst exhaust gas aftertreatment sensor system 157 only has the firstsensor 202 and the second sensor 204 downstream of the ammonia slipcatalyst 117.

The first exhaust gas aftertreatment sensor system 157 can include athird sensor 206 (e.g., sensing unit, sensing module, sensing component,sensor unit, sensor unit, sensor component, etc.) that is configured tomeasure the parameter in the exhaust gas aftertreatment system 102. Thethird sensor 206 includes at least one of a multiple gas sensor, aparticulate matter sensor, a particulate number sensor, or a deltapressure sensor. The third sensor 206 is at least one of the thirdengine-out NO_(x) sensor 150 c, the third particulate sensor 160 c, thethird NH₃ sensor 162 c, or the third system-out NO_(x) sensor 164 c. Thethird sensor 206 can be a tertiary sensor.

The third sensor 206 is disposed proximate the first sensor 202 and thesecond sensor 204. As shown in FIG. 2 the second sensor 204 and thethird sensor 206 are located on a plane perpendicular to the flow of theexhaust gas in the exhaust gas aftertreatment system 102. The thirdsensor 206 is located at a distance D₃ from the center point C of theexhaust gas conduit 190 of the exhaust gas conduit system 106 asmeasured along a radius of the exhaust gas conduit 190. The third sensor206 is coupled to the exhaust gas conduit 190. The second sensor 204 andthe third sensor 206 are separated by an angle β. In one embodiment, theangle β is 90 degrees. However, in various applications the angles maybe substantially equal to 40 degrees, 50 degrees, 60 degrees, 70degrees, 80 degrees, 90 degrees 100 degrees, 110 degrees, 120 degrees,130 degrees, or other similar values. The first sensor 202, secondsensor 204 and the third sensor 206 can be designed to function with agas sampling apparatus intended to pull a representative sample from theexhaust gas aftertreatment system 102 (e.g., NO_(x) sampling wheel). Theadditional sensors (e.g., second sensor 204, third sensor 206, etc.) canreduce unnecessary service events. The failure of a single sensor doesnot necessitate a service event, but it is stored in the aftertreatmentcontroller memory and can be replaced at a subsequent service eventtriggered by a failure unrelated to the sensor system.

In some embodiments, the first exhaust gas aftertreatment sensor system157 only has the first sensor 202, the second sensor 204, and the thirdsensor 206 downstream of the internal combustion engine 108 and upstreamof the oxidation catalyst 111. In some embodiments, the first exhaustgas aftertreatment sensor system 157 only has the first sensor 202, thesecond sensor 204, and the third sensor 206 upstream of the conversioncatalyst 116 and downstream of the particulate filter 112. In someembodiments, the first exhaust gas aftertreatment sensor system 157 onlyhas the first sensor 202, the second sensor 204, and the third sensor206 upstream of the ammonia slip catalyst 117 and downstream of theconversion catalyst 116. In some embodiments, the first exhaust gasaftertreatment sensor system 157 only has the first sensor 202, thesecond sensor 204, and the third sensor 206 downstream of the ammoniaslip catalyst 117.

In some embodiments, the sensors can include a filter 208. For example,the first sensor 202, second sensor 204, and the third sensor 206 caninclude the filter 208. The filter 208 can inhibit or prevent intrusionof particulate matter and/or liquid water droplets into the sensorswhile facilitating diffusion and flow of gas molecules into any of thefirst engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, the third engine-out NO_(x) sensor 150 c, the first NH₃sensor 162 a, the second NH₃ sensor 162 b, the third NH₃ sensor 162 c,the first system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, or the third system-out NO_(x) sensor 164 c. The filter208 can include a filter screen. The filter 208 may or may not beincluded with the sensors. The filter 208 can be disposed at a side ofthe sensor exposed to the exhaust gas of the exhaust gas aftertreatmentsystem. The filter 208 can include the engine-out NO_(x) filter 151, NH₃filter 163 or the system-out NO_(x) filter 165.

FIG. 3 illustrates a cross-sectional view of the exhaust gasaftertreatment system shown in FIG. 1, taken along plane A-A, plane B-B,plane C-C, or plane D-D, according to an embodiment. The first exhaustgas aftertreatment sensor system 157 includes a first sensor 202 that isconfigured to measure a parameter in the exhaust gas aftertreatmentsystem 102 and a second sensor 204 configured to measure the parameterin the exhaust gas aftertreatment system 102. The second sensor 204 isdisposed proximate the first sensor 202. For example, the first sensor202 and the second sensor 204 is located on a plane perpendicular to theflow of exhaust gas in the exhaust gas aftertreatment system 102. Thefirst sensor 202 is located at the distance Di from a center point C ofthe exhaust gas conduit 190 of the exhaust gas conduit system 106 asmeasured along a radius of the exhaust gas conduit 190. The first sensor202 is coupled to the exhaust gas conduit 190. Similarly, the secondsensor 204 is located at the distance D₂ from the center point C of theexhaust gas conduit 190 of the exhaust gas conduit system 106 asmeasured along a radius of the exhaust gas conduit 190. The secondsensor 204 is coupled to the exhaust gas conduit 190. The location ofthe first sensor 202 and the second sensor 204 can enable the firstexhaust gas aftertreatment sensor system 157 to measure the uniformityof the gas concentration. If the gas concentration is non-uniform, adeposit removal or other diagnostic event can be triggered. The firstsensor 202 and the second sensor 204 are separated by an angle α. In oneembodiment, the angle α is approximately 30 degrees. However, in variousapplications the angles may be substantially equal to 20 degrees, 30degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90degrees 100 degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees,150 degrees, 160 degrees, 170 degrees, 180 degrees, or other similarvalues.

The first exhaust gas aftertreatment sensor system 157 can includes athird sensor 206 that is configured to measure the parameter in theexhaust gas aftertreatment system 102. The third sensor 206 is at leastone of a multiple gas sensor, a particulate matter sensor, a particulatenumber sensor, or a delta pressure sensor. The third sensor 206 can be atertiary sensor. The third sensor 206 is disposed proximate the firstsensor 202 and the second sensor 204. For example, the second sensor 204and the third sensor 206 is located on a plane perpendicular to the flowof exhaust gas in the exhaust gas aftertreatment system 102. The thirdsensor 206 is located at the distance D₃ from the center point C of theexhaust gas conduit 190 of the exhaust gas conduit system 106 asmeasured along a radius of the exhaust gas conduit 190. The third sensor206 is coupled to the exhaust gas conduit 190. The second sensor 204 andthe third sensor 206 are separated by an angle β. In one embodiment, theangle β is approximately 30 degrees. However, in various applicationsthe angles may be substantially equal to 20 degrees, 30 degrees, 40degrees, 50 degrees, 60 degrees, 70 degrees, 80 degrees, 90 degrees 100degrees, 110 degrees, 120 degrees, 130 degrees, 140 degrees, 150degrees, 160 degrees, 170 degrees, 180 degrees, or other similar values.

IV. Overview of a Second Vehicle System

FIG. 4 illustrates an example vehicle system 400. The vehicle system 400includes an exhaust gas aftertreatment system 402 having a reductantdelivery system 404 for an exhaust gas conduit system 406. The vehiclesystem 400 also includes an internal combustion engine 408 (e.g., dieselinternal combustion engine, diesel hybrid internal combustion engine,gasoline internal combustion engine, natural gas internal combustionengine, liquid propane internal combustion engine, etc.) which producesexhaust gas that is received by the exhaust gas aftertreatment system402. The internal combustion engine 408 receives fuel (e.g., dieselfuel, gasoline, natural gas, liquid propane, etc.) from a fuel tank 410(e.g., reservoir, etc.). The fuel tank 410 is configured to bereplenished (e.g., by a user, etc.).

The exhaust gas aftertreatment system 402 also includes an oxidationcatalyst 411 (e.g., a diesel oxidation catalyst (DOC), etc.). Theoxidation catalyst 411 is configured to (e.g., structured to, able to,etc.) promote oxidation of hydrocarbons and/or carbon monoxide inexhaust gas produced by the internal combustion engine 408 and flowingin the exhaust gas conduit system 406. In some implementations, theoxidation catalyst 411 may be omitted.

The exhaust gas aftertreatment system 402 also includes a particulatefilter 412 (e.g., a diesel particulate filter (DPF), a gasolineparticulate filter (GPF), etc.). The particulate filter 412 isconfigured to remove particulate matter, such as soot, from the exhaustgas provided by the oxidation catalyst 411. The particulate filter 412includes an inlet, where the exhaust gas is received, and an outlet,where the exhaust gas exits after having particulate mattersubstantially filtered from the exhaust gas and/or converting theparticulate matter into carbon dioxide. In some implementations, theparticulate filter 412 may be omitted.

The exhaust gas aftertreatment system 402 also includes a decompositionchamber 414 (e.g., reactor, reactor pipe, compact mixer, mixer, etc.).The decomposition chamber 414 is configured to convert a reductant intoammonia. The reductant may be, for example, urea, diesel exhaust fluid(DEF), Adblue®, a urea water solution (UWS), an aqueous urea solution(AUS) (e.g., AUS32, etc.), and other similar fluids. The decompositionchamber 414 includes an inlet in fluid communication with theparticulate filter 412 to receive the exhaust gas containing NO_(x)emissions and an outlet for the exhaust gas, NO_(x) emissions, ammonia,and/or reductant to flow from the decomposition chamber 414.

The exhaust gas aftertreatment system 402 also includes a conversioncatalyst 416 (e.g., a selective catalytic reduction (SCR) catalyst, acopper-zeolite SCR catalyst, etc.). The conversion catalyst 416 isconfigured to assist in the reduction of NO_(x) emissions byaccelerating a NO_(x) reduction process between the ammonia and theNO_(x) of the exhaust gas into diatomic nitrogen, water, and/or carbondioxide. The conversion catalyst 416 includes an inlet in fluidcommunication with the decomposition chamber 414 from which exhaust gasand reductant are received and an outlet in fluid communication with anend of the exhaust gas conduit system 406.

The decomposition chamber 414 is located upstream of the conversioncatalyst 416. As a result, the reductant is injected upstream of theconversion catalyst 416 such that the conversion catalyst 416 receives amixture of the reductant and exhaust gas. The reductant droplets undergothe processes of evaporation, thermolysis, and hydrolysis to formnon-NO_(x) emissions (e.g., gaseous ammonia, etc.) within the exhaustgas conduit system 406.

The exhaust gas aftertreatment system 402 also includes an ammonia slipcatalyst (ASC) 417. The ammonia slip catalyst 417 is configured toassist in the conversion of NH₃ into diatomic nitrogen. The ammonia slipcatalyst 417 is located downstream of the conversion catalyst 416.

The reductant delivery system 404 includes a dosing module 418 (e.g.,doser, etc.) configured to dose the reductant into the decompositionchamber 414 (e.g., via an injector, etc.). The dosing module 418 ismounted to the decomposition chamber 414 such that the dosing module 418may dose the reductant into the exhaust gas flowing in the exhaust gasconduit system 406. The dosing module 418 may include an insulator(e.g., thermal insulator, etc.) and/or isolator (e.g., vibrationalisolator, etc.) interposed between a portion of the dosing module 418and the portion of the decomposition chamber 414 on which the dosingmodule 418 is mounted.

The dosing module 418 is fluidly coupled to (e.g., fluidly configured tocommunicate with, etc.) a reductant source 420 (e.g., reductant tank,reductant reservoir, etc.). The reductant source 420 may includemultiple reductant sources 420. The reductant source 420 may be, forexample, a DEF tank containing Adblue®. A reductant pump 421 (e.g.,supply unit, etc.) is used to pressurize the reductant from thereductant source 420 for delivery to the dosing module 418. In someembodiments, the reductant pump 421 is pressure controlled (e.g.,controlled to obtain a target pressure, etc.). The reductant pump 421may draw the reductant through a reductant filter 422. The reductantfilter 422 filters (e.g., strains, etc.) the reductant prior to thereductant being provided to internal components (e.g., pistons, vanes,etc.) of the reductant pump 421. For example, the reductant filter 422may inhibit or prevent the transmission of solids (e.g., solidifiedreductant, contaminants, etc.) to the internal components of thereductant pump 421. In this way, the reductant filter 422 may facilitateprolonged desirable operation of the reductant pump 421.

In some embodiments, the reductant pump 421 is coupled to a chassis of avehicle associated with the exhaust gas aftertreatment system 402.

The dosing module 418 includes at least one injector 424 (e.g.,reductant injector, etc.). Each injector 424 is configured to dose thereductant into the exhaust gas (e.g., within the decomposition chamber414, etc.). The injector 424 may be positioned to cause the reductant toachieve a target uniformity index (UI) within the exhaust gas at atarget location (e.g., at an inlet of the conversion catalyst 416,etc.).

In some embodiments, the reductant delivery system 404 also includes anair pump 426. In these embodiments, the air pump 426 draws air from anair source 428 (e.g., air intake, atmosphere, etc.) and through an airfilter 430 disposed upstream of the air pump 426. The air filter 430filters the air prior to the air being provided to internal components(e.g., pistons, vanes, etc.) of the air pump 426. For example, the airfilter 430 may inhibit or prevent the transmission of solids (e.g.,debris, branches, dirt, etc.) to the internal components of the air pump426. In this way, the air filter 430 may facilitate prolonged desirableoperation of the air pump 426. The air pump 426 provides the air to thedosing module 418 via a conduit. The dosing module 418 is configured tomix the air and the reductant into an air-reductant mixture and toprovide the air-reductant mixture into the decomposition chamber 414. Inother embodiments, the reductant delivery system 404 does not includethe air pump 426, the air source 428, or the air filter 430. In suchembodiments, the dosing module 418 is not configured to mix thereductant with air.

The dosing module 418 and the reductant pump 421 are also electricallyor communicatively coupled to an exhaust gas aftertreatment systemcontroller 432. The exhaust gas aftertreatment system controller 432 isconfigured to control the dosing module 418 to dose the reductant intothe decomposition chamber 414. The exhaust gas aftertreatment systemcontroller 432 may also be configured to control the reductant pump 421.

The exhaust gas aftertreatment system controller 432 includes aprocessing circuit 434. The processing circuit 434 includes a processor436 and a memory 438. The processor 436 may include a microprocessor, anapplication-specific integrated circuit (ASIC), a field-programmablegate array (FPGA), etc., or combinations thereof. The memory 438 mayinclude, but is not limited to, electronic, optical, magnetic, or anyother storage or transmission device capable of providing a processor,ASIC, FPGA, etc. with program instructions. This memory 438 may includea memory chip, Electrically Erasable Programmable Read-Only Memory(EEPROM), Erasable Programmable Read Only Memory (EPROM), flash memory,or any other suitable memory from which the exhaust gas aftertreatmentsystem controller 432 can read instructions. The instructions mayinclude code from any suitable programming language. The memory 438 mayinclude various modules that include instructions which are configuredto be implemented by the processor 436.

While not shown, it is understood that the internal combustion engine408 includes various components, such as cylinders, pistons, fuelinjectors, air intakes, and other similar components. In someapplications, the internal combustion engine 408 may include aturbocharger, an exhaust gas recirculation (EGR) system, a waste heatrecovery (WHR) system, and/or other similar components.

In some implementations, the particulate filter 412 may be positioneddownstream of the decomposition chamber 414. For instance, theparticulate filter 412 and the conversion catalyst 416 may be combinedinto a single unit. In some implementations, the dosing module 418 mayinstead be positioned downstream of a turbocharger or upstream of aturbocharger. In some embodiments, more than one SCR catalyst may beused.

V. Overview of a Second Exhaust Gas Aftertreatment Sensor System

The vehicle system 400 also includes a second exhaust gas aftertreatmentsensor system 457 (e.g., sensing system, sensing assembly, sensorarrangement, accessory sensing system, accessory sensor system, etc.).The second exhaust gas aftertreatment sensor system 457 includes a firstengine-out NO_(x) sensor 450 a (e.g., sensing unit, sensing module,sensing component, sensor unit, sensor unit, sensor component, etc.).The first engine-out NO_(x) sensor 450 a is located upstream of theoxidation catalyst 411 and downstream of the internal combustion engine408. The second exhaust gas aftertreatment sensor system 457 includes asecond engine-out NO_(x) sensor 450 b (e.g., sensing unit, sensingmodule, sensing component, sensor unit, sensor unit, sensor component,etc.). The second engine-out NO_(x) sensor 450 b may be located upstreamof the first engine-out NO_(x) sensor 450 a, downstream of the firstengine-out NO_(x) sensor 450 a, or parallel with the first engine-outNO_(x) sensor 450 a. The second engine-out NO_(x) sensor 450 b islocated upstream of the oxidation catalyst 411 and downstream of theinternal combustion engine 408. The second exhaust gas aftertreatmentsensor system 457 includes a third engine-out NO_(x) sensor 450 c (e.g.,sensing unit, sensing module, sensing component, sensor unit, sensorunit, sensor component, etc.). The third engine-out NO_(x) sensor 450 cis located upstream of the oxidation catalyst 411 and downstream of theinternal combustion engine 408. The third engine-out NO_(x) sensor 450 cmay be located upstream of the first engine-out NO_(x) sensor 450 a,downstream of the first engine-out NO_(x) sensor 450 a, or parallel withthe first engine-out NO_(x) sensor 450 a and upstream of the secondengine-out NO_(x) sensor 450 b, downstream of the second engine-outNO_(x) sensor 450 b, parallel with the second engine-out NO_(x) sensor450 b.

The first engine-out NO_(x) sensor 450 a, the second engine-out NO_(x)sensor 450 b, and the third engine-out NO_(x) sensor 450 c are eachconfigured to independently determine a NO_(x) concentration of theexhaust gas exiting the internal combustion engine 408. The exhaust gasaftertreatment system controller 432 is configured to use these NO_(x)concentrations to, for example, control the dosing module 418 to dosethe reductant into the decomposition chamber 414.

The first engine-out NO_(x) sensor 450 a can include an engine-outNO_(x) filter 451. The engine-out NO_(x) filter 451 can inhibit orprevent intrusion of particulate matter and/or liquid water dropletsinto any of the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, or the third engine-out NO_(x) sensor450 c while facilitating diffusion and flow of exhaust gas moleculesinto any of the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, or the third engine-out NO_(x) sensor450 c. The engine-out NO_(x) filter 451 can include a filter screen. Thesecond engine-out NO_(x) sensor 450 b can include the engine-out NO_(x)filter 451. The third engine-out NO_(x) sensor 450 c can include theengine-out NO_(x) filter 451. The engine-out NO_(x) filter 451 may ormay not be included with any of the first engine-out NO_(x) sensor 450a, the second engine-out NO_(x) sensor 450 b, or the third engine-outNO_(x) sensor 450 c.

The second engine-out NO_(x) sensor 450 b is located downstream of thefirst engine-out NO_(x) sensor 450 a and upstream of the thirdengine-out NO_(x) sensor 450 c. The location of the first engine-outNO_(x) sensor 450 a relative to the second engine-out NO_(x) sensor 450b can facilitate the measurement of exhaust gas volumetric flow. Forexample, the first engine-out NO_(x) sensor 450 a can be axiallyseparated from the second engine-out NO_(x) sensor 450 b by 2 inches.However, in various application, the separation between first engine-outNO_(x) sensor 450 a and the second engine-out NO_(x) sensor 450 b may besubstantially equal to 0.5 inches, 1 inches, 1.5 inches, 2 inches, 2.5inches, 3 inches or other similar values. The third engine-out NO_(x)sensor 450 c can be axially separated from the second engine-out NO_(x)sensor 450 b by 2 inches. However, in various application, theseparation between third engine-out NO_(x) sensor 450 c and the secondengine-out NO_(x) sensor 450 b may be substantially equal to 0.5 inches,1 inches, 1.5 inches, 2 inches, 2.5 inches, 3 inches or other similarvalues.

The second exhaust gas aftertreatment sensor system 457 also includes afirst particulate sensor 460 a (e.g., particulate matter sensor,particulate number sensor, etc.). The first particulate sensor 460 a islocated upstream of the conversion catalyst 416 (e.g., upstream of thedecomposition chamber 414, within the decomposition chamber 414, etc.)and downstream of the particulate filter 412. The second exhaust gasaftertreatment sensor system 457 includes a second particulate sensor460 b (e.g., particulate matter sensor, particulate number sensor,etc.). The second particulate sensor 460 b is located upstream of theconversion catalyst 416 (e.g., upstream of the decomposition chamber414, within the decomposition chamber 414, etc.) and downstream of theparticulate filter 412. The second exhaust gas aftertreatment sensorsystem 457 includes a third particulate sensor 460 c (e.g., particulatematter sensor, particulate number sensor, etc.). The third particulatesensor 460 c is located upstream of the conversion catalyst 416 (e.g.,upstream of the decomposition chamber 414, within the decompositionchamber 414, etc.) and downstream of the particulate filter 412.

The first particulate sensor 460 a, the second particulate sensor 460 b,and the third particulate sensor 460 c are each configured toindependently determine an amount of particulate matter within theexhaust gas downstream of the particulate filter 412 and upstream of theconversion catalyst 416. The exhaust gas aftertreatment systemcontroller 432 is configured to use these amounts of particulate matterto, for example, control the dosing module 418 to dose the reductantinto the decomposition chamber 414. For the first particulate sensor 460a, the second particulate sensor 460 b, or the third particulate sensor460 c an isokinetic sampling probe can be used to ensure representativesampling and minimal particle loss due to gas velocity gradients nearthe sampling probe.

The second particulate sensor 460 b is located downstream of the firstparticulate sensor 460 a and upstream of the third particulate sensor460 c. The location of the first particulate sensor 460 a relative tothe second particulate sensor 460 b can facilitate the measurement ofexhaust gas volumetric flow. For example, the first particulate sensor460 a can be axially separated from the second particulate sensor 460 bby 2 inches. However, in various application, the separation betweenfirst particulate sensor 460 a and the second particulate sensor 460 bmay be substantially equal to 0.5 inches, 1 inches, 1.5 inches, 2inches, 2.5 inches, 3 inches or other similar values. The thirdparticulate sensor 460 c can be axially separated from the secondparticulate sensor 460 b by 2 inches. However, in various application,the separation between third particulate sensor 460 c and the secondparticulate sensor 460 b may be substantially equal to 0.5 inches, 1inches, 1.5 inches, 2 inches, 2.5 inches, 3 inches or other similarvalues.

The second exhaust gas aftertreatment sensor system 457 also includes afirst NH₃ sensor 462 a (e.g., sensing unit, sensing module, sensingcomponent, sensor unit, sensor unit, sensor component, etc.). The firstNH₃ sensor 462 a is located upstream of the ammonia slip catalyst 417and downstream of the conversion catalyst 416. The second exhaust gasaftertreatment sensor system 457 includes a second NH₃ sensor 462 b(e.g., sensing unit, sensing module, sensing component, sensor unit,sensor unit, sensor component, etc.). The second NH₃ sensor 462 b islocated upstream of the ammonia slip catalyst 417 and downstream of theconversion catalyst 416. The second exhaust gas aftertreatment sensorsystem 457 includes a third NH₃ sensor 462 c (e.g., sensing unit,sensing module, sensing component, sensor unit, sensor unit, sensorcomponent, etc.). The third NH₃ sensor 462 c is located upstream of theammonia slip catalyst 417 and downstream of the conversion catalyst 416.

The first NH₃ sensor 462 a, the second NH₃ sensor 462 b, and the thirdNH₃ sensor 462 c are each configured to independently determine an NH₃concentration exiting the conversion catalyst 416. The exhaust gasaftertreatment system controller 432 is configured to use these NH₃concentrations to, for example, control the dosing module 418 to dosethe reductant into the decomposition chamber 414.

The first NH₃ sensor 462 a can include a NH₃ filter 463. The NH₃ filter463 can inhibit or prevent intrusion of particulate matter and/or liquidwater droplets into any of the first NH₃ sensor 462 a, the second NH₃sensor 462 b, or the third NH₃ sensor 462 c while facilitating diffusionand flow of gas molecules into any of the first NH₃ sensor 462 a, thesecond NH₃ sensor 462 b, or the third NH₃ sensor 462 c. The NH₃ filter463 can include a filter screen. The second NH₃ sensor 462 b can includethe NH₃ filter 463. The third NH₃ sensor 462 c can include the NH₃filter 463. The NH₃ filter 463 may or may not be included with the firstNH₃ sensor 462 a, the second NH₃ sensor 462 b, or the third NH₃ sensor46 c.

The second NH₃ sensor 460 b is located downstream of the first NH₃sensor 462 a and upstream of the third NH₃ sensor 462 c. The location ofthe first NH₃ sensor 462 a relative to the second NH₃ sensor 462 b canfacilitate the measurement of exhaust gas volumetric flow. For example,the first NH₃ sensor 462 a can be axially separated from the second NH₃sensor 462 b by 2 inches. However, in various application, theseparation between first NH₃ sensor 462 a and the second NH₃ sensor 462b may be substantially equal to 0.5 inches, 1 inches, 1.5 inches, 2inches, 2.5 inches, 3 inches or other similar values. The third NH₃sensor 462 c can be axially separated from the second NH₃ sensor 462 bby 2 inches. However, in various application, the separation betweenthird NH₃ sensor 462 c and the second NH₃ sensor 462 b may besubstantially equal to 0.5 inches, 1 inches, 1.5 inches, 2 inches, 2.5inches, 3 inches or other similar values.

The second exhaust gas aftertreatment sensor system 457 also includes afirst system-out NO_(x) sensor 464 a (e.g., sensing unit, sensingmodule, sensing component, sensor unit, sensor unit, sensor component,etc.). The first system-out NO_(x) sensor 464 a is located downstream ofthe ammonia slip catalyst 417. The second exhaust gas aftertreatmentsensor system 457 includes a second system-out NO_(x) sensor 464 b(e.g., sensing unit, sensing module, sensing component, sensor unit,sensor unit, sensor component, etc.). The second system-out NO_(x)sensor 464 b is located downstream of the ammonia slip catalyst 417. Thesecond exhaust gas aftertreatment sensor system 457 includes a thirdsystem-out NO_(x) sensor 464 c (e.g., sensing unit, sensing module,sensing component, sensor unit, sensor unit, sensor component, etc.).The third system-out NO_(x) sensor 464 c is located downstream of theammonia slip catalyst 417. The first system-out NO_(x) sensor 464 a, thesecond system-out NO_(x) sensor 464 b, and the third system-out NO_(x)sensor 464 c are configured to determine NO_(x) concentrations of theexhaust gas exiting the exhaust gas aftertreatment system 402 (e.g.,downstream of the ammonia slip catalyst 417, etc.). The exhaust gasaftertreatment system controller 432 is configured to use these NO_(x)concentrations to, for example, control the dosing module 418 to dosethe reductant into the decomposition chamber 414.

The first system-out NO_(x) sensor 464 a can include a system-out NO_(x)filter 465. The system-out NO_(x) filter 465 can inhibit or preventintrusion of particulate matter and/or liquid water droplets into any ofthe first system-out NO_(x) sensor 464 a, the second system-out NO_(x)sensor 464 b, or the third system-out NO_(x) sensor 464 c whilefacilitating diffusion and flow of exhaust gas molecules into any of thefirst system-out NO_(x) sensor 464 a, the second system-out NO_(x)sensor 464 b, or the third system-out NO_(x) sensor 464 c. Thesystem-out NO_(x) filter 465 can include a filter screen. The secondsystem-out NO_(x) sensor 464 b can include the system-out NO_(x) filter465. The third system-out NO_(x) sensor 464 c can include the system-outNO_(x) filter 465. The system-out NO_(x) filter 465 may or may not beincluded with the first system-out NO_(x) sensor 464 a, the secondsystem-out NO_(x) sensor 464 b, or the third system-out NO_(x) sensor464 c.

The location of the first sensor 202 and the second sensor 204 canfacilitate the measurement of exhaust gas volumetric flow. In aconfiguration with axially adjacent sensors of the same function, thetime between when a concentration change affects a sensor could be usedto estimate the exhaust volumetric flow. For example, the firstsystem-out NO_(x) sensor 464 a could be axially separated from thesecond system-out NO_(x) sensor 464 b by 2 inches. However, in variousapplication, the separation between first system-out NO_(x) sensor 464 aand the second system-out NO_(x) sensor 464 b may be substantially equalto 0.5 inches, 1 inches, 1.5 inches, 2 inches, 2.5 inches, 3 inches orother similar values. The third system-out NO_(x) sensor 464 c could beaxially separated from the second system-out NO_(x) sensor 464 b by 2inches. However, in various application, the separation between thirdsystem-out NO_(x) sensor 464 c and the second system-out NO_(x) sensor464 b may be substantially equal to 0.5 inches, 1 inches, 1.5 inches, 2inches, 2.5 inches, 3 inches or other similar values. The secondsystem-out NO_(x) sensor 464 b can be located downstream from the firstsystem-out NO_(x) sensor 464 a. The second system-out NO_(x) sensor 464b could respond to an increase in NO_(x) a certain time after theupstream sensor, in this case, the first system-out NO_(x) sensor 464 a.The volume of the exhaust piping separating the first system-out NO_(x)sensor 464 a and the second system-out NO_(x) sensor 464 b can be usedto estimate the volumetric flow rate.

The second exhaust gas aftertreatment sensor system 457 also includesthe exhaust gas aftertreatment system controller 432. The exhaust gasaftertreatment system controller 432 is configured to communicate withthe first engine-out NO_(x) sensor 450 a, the second engine-out NO_(x)sensor 450 b, the third engine-out NO_(x) sensor 450 c, the firstparticulate sensor 460 a, the second particulate sensor 460 b, the thirdparticulate sensor 460 c, the first NH₃ sensor 462 a, the second NH₃sensor 462 b, the third NH₃ sensor 462 c, the first system-out NO_(x)sensor 464 a, the second system-out NO_(x) sensor 464 b, and/or thethird system-out NO_(x) sensor 464 c. The exhaust gas aftertreatmentsystem controller 432 can be implemented across several controllers. Forexample, a first exhaust gas aftertreatment system controller cancontrol the first engine-out NO_(x) sensor 450 a, the first particulatesensor 460 a, the first NH₃ sensor 462 a, and/or the first system-outNO_(x) sensor 464 a. A second exhaust gas aftertreatment systemcontroller can control the second engine-out NO_(x) sensor 450 b, thesecond particulate sensor 460 b, the second NH₃ sensor 462 b, and/or thesecond system-out NO_(x) sensor 464 b. A third exhaust gasaftertreatment system controller can control the third engine-out NO_(x)sensor 450 c, the third particulate sensor 460 c, the third NH₃ sensor462 c, and/or the third system-out NO_(x) sensor 464 c.

The memory 438 also includes a sensor determination module 453 (e.g.,circuit, etc.). The sensor determination module 453 determines, out of aset of sensors (e.g., a first set of sensors including the firstengine-out NO_(x) sensor 450 a, the second engine-out NO_(x) sensor 450b, and the third engine-out NO_(x) sensor 450 c, a second set of sensorsincluding the first particulate sensor 460 a, the second particulatesensor 460 b, and the third particulate sensor 460 c, a third set ofsensors including the first NH₃ sensor 462 a, the second NH₃ sensor 462b, and the third NH₃ sensor 462 c, a fourth set of sensors including thefirst system-out NO_(x) sensor 464 a, the second system-out NO_(x)sensor 464 b, and the third system-out NO_(x) sensor 464 c, etc.), whichsensor (e.g., the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, the third engine-out NO_(x) sensor 450c, the first particulate sensor 460 a, the second particulate sensor 460b, the third particulate sensor 460 c, the first NH₃ sensor 462 a, thesecond NH₃ sensor 462 b, the third NH₃ sensor 462 c, the firstsystem-out NO_(x) sensor 464 a, the second system-out NO_(x) sensor 464b, the third system-out NO_(x) sensor 464 c) is the primary sensor. Forexample, the sensor determination module 453 can determine that of thefirst engine-out NO_(x) sensor 450 a, the second engine-out NO_(x)sensor 450 b, and the third engine-out NO_(x) sensor 450 c, the firstengine-out NO_(x) sensor 450 a is the primary sensor. In anotherexample, the sensor determination module 453 can determine that of thefirst NH₃ sensor 462 a, the second NH₃ sensor 462 b, and the third NH₃sensor 462 c, the second NH₃ sensor 462 b is the primary sensor.

The memory 438 also includes a sensor operation module 455 (e.g.,circuit, etc.). The sensor operation module 455 can receive sensorvalues. For example, the sensor operation module 455 can receive a firstsensor value from the first engine-out NO_(x) sensor 450 a, the firstparticulate sensor 460 a, the first NH₃ sensor 462 a, and/or the firstsystem-out NO_(x) sensor 464 a. The sensor operation module 455 canreceive a second sensor value from the second engine-out NO_(x) sensor450 b, the second particulate sensor 460 b, the second NH₃ sensor 462 b,and/or the second system-out NO_(x) sensor 464 b. The sensor operationmodule 455 can receive a third sensor value from the third engine-outNO_(x) sensor 450 c, the third particulate sensor 460 c, the third NH₃sensor 462 c, and/or the third system-out NO_(x) sensor 464 c.

The memory 438 also includes a sensor value difference module 454 (e.g.,circuit, etc.). The sensor value difference module 454 stores adifference D₁₋₂ between a first sensor value and a second sensor value.The exhaust gas aftertreatment system controller 432 can compare theD₁₋₂ to a threshold value to determine if a sensor is failing or hasfailed. The sensor value difference module 454 stores a difference D₂₋₃between a second sensor value and a third sensor value. The exhaust gasaftertreatment system controller 432 can compare the D₂₋₃ to a thresholdvalue to determine if a sensor is failing or has failed. The sensorvalue difference module 454 stores a difference D_(1-C) between a firstsensor value and a calculated sensor value. The exhaust gasaftertreatment system controller 432 can compare the D_(1-C) to athreshold value to determine if a sensor is failing or has failed. Thesensor value difference module 454 stores a difference D_(2-C) between asecond sensor value and a calculated sensor value. The exhaust gasaftertreatment system controller 432 can compare the D_(2-C) to athreshold value to determine if a sensor is failing or has failed. Thesensor value difference module 454 stores a difference D_(3-C) between athird sensor value and a calculated sensor value. The exhaust gasaftertreatment system controller 432 can compare the D_(3-C) to athreshold value to determine if a sensor is failing or has failed. TheD₁₋₂ may be approximately equal to 10 ppm, 5 ppm, 15 ppm, 20 ppm, orother similar values. The D₂₋₃ may be approximately equal to 10 ppm, 5ppm, 15 ppm, 20 ppm, or other similar values. The D_(1-C) may beapproximately equal to 10 ppm, 5 ppm, 15 ppm, 20 ppm, or other similarvalues. The D_(2-C) may be approximately equal to 10 ppm, 5 ppm, 15 ppm,20 ppm, or other similar values. The D_(3-C) may be approximately equalto 10 ppm, 5 ppm, 15 ppm, 20 ppm, or other similar values.

FIG. 5 illustrates a diagram of an example sensor, according to anembodiment. The first sensor 202 can include one or more sensingelements 502. Each of the sensing elements can include, for example, oneor more resistive elements, one or more electrochemical cells, etc. Theresistance of the resistive elements can change based on an amount ofparticulate matter deposited on the resistive element. Theelectrochemical cells can measure a gas concentration (e.g., NO_(x)concentration). For example, the sensing element 502 can include a firstelectrochemical cell and a second electrochemical cell. The firstelectrochemical cell can be configured to pump O₂ out of a gas sample.The O₂ in the first electrochemical cell can be reduced to form O²⁻ ionswhich can then be pumped through a zirconia electrolyte by applying afirst pumping current. The first pumping current is proportional to theO₂ concentration. The gas sample can diffuse into the secondelectrochemical cell configured to decompose NO_(x) into N₂ and O₂. TheO₂ in the second electrochemical cell can be reduced to form O²⁻ ionswhich can then be pumped through a zirconia electrolyte by applying asecond pumping current. The second pumping current is proportional tothe 02 concentration from the NO_(x) decomposition. The second pumpingcurrent can be used to determine the NO_(x) concentration in the gassample.

For example, the first sensor 202 can be a sensing module that includesa single sensing element 502. The first sensor 202 can be a sensingmodule that includes two sensing elements 502. The first sensor 202 canbe a sensing module that includes three sensing elements 502. The firstsensor 202 can include more than three sensing elements 502. A sensorwith multiple sensing elements 502 can include sensing elements 502 thatmeasure the same parameter or that measure different parameters. Thesensor with multiple sensing elements 502 can provide spatial proximityof the multiple sensing elements 502. The sensor with multiple sensingelements 502 can be of lower cost to install and manufacture than asensor with a single sensing element 502. The multiple sensing elements502 of the sensor can make measurements on the same gas volume, whichcould contribute to reducing uncertainty in the measurements based onspatial gas concentration variation that other separate sensing modulesor sensors could measure.

FIG. 6A illustrates a diagram of an example sensor with a single sensingelement 502, according to an embodiment. The first sensor 202 includes asubstrate 602, which can include a refractory material such as zirconiaor yttria-stabilized zirconia. The sensing element 502 is disposed onthe substrate 602. The substrate 602 includes a first side 604 (e.g.,top side) and a second side 606 (e.g., bottom side). The first side 604and the second side 606 can be different sides (e.g., opposite sides,adjacent sides, etc.) of the substrate 602.

FIG. 6B illustrates a diagram of an example sensor with multiple sensingelements 502, according to an embodiment. For example, two or moresensing elements 502 can be disposed on the substrate 602. The firstsensor 202 can include a first sensing element 502 and a second sensingelement 502. The first sensing element 502 and the second sensingelement 502 can be located on the same side of the substrate 602. Forexample, the first sensing element 502 and the second sensing element502 can be located on the first side 604 of the substrate 602.Alternatively, the first sensing element 502 and the second sensingelement 502 can be located on different sides of the substrate 602. Forexample, the first sensing element 502 can be located on the first side604 of the substrate 602, while the second sensing element 502 can belocated on the second side 606 of the substrate 602. Regardless of theconfiguration, the first sensing element 502 and the second sensingelement 502 can make measurements on the same gas volume.

VI. Example Serial Process for an Exhaust Gas Aftertreatment System

FIG. 7 is a flow chart of a serial process 700 (e.g., method, procedure,etc.) for controlling operation of one or more sensors in the exhaustgas aftertreatment system 102 or the exhaust gas aftertreatment system402. The serial process 700 is described with reference to the firstsensor 202 and the second sensor 204. It is understood that the firstsensor 202 is any of the first engine-out NO_(x) sensor 150 a, thesecond engine-out NO_(x) sensor 150 b, the third engine-out NO_(x)sensor 150 c, the first particulate sensor 160 a, the second particulatesensor 160 b, the third particulate sensor 160 c, the first NH₃ sensor162 a, the second NH₃ sensor 162 b, the third NH₃ sensor 162 c, thefirst system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, the third system-out NO_(x) sensor 164 c, the firstengine-out NO_(x) sensor 450 a, the second engine-out NO_(x) sensor 450b, the third engine-out NO_(x) sensor 450 c, the first particulatesensor 460 a, the second particulate sensor 460 b, the third particulatesensor 460 c, the first NH₃ sensor 462 a, the second NH₃ sensor 462 b,the third NH₃ sensor 462 c, the first system-out NO_(x) sensor 464 a,the second system-out NO_(x) sensor 464 b, or the third system-outNO_(x) sensor 464 c.

Similarly, it is understood that the second sensor 204 is any of thefirst engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, the third engine-out NO_(x) sensor 150 c, the firstparticulate sensor 160 a, the second particulate sensor 160 b, the thirdparticulate sensor 160 c, the first NH₃ sensor 162 a, the second NH₃sensor 162 b, the third NH₃ sensor 162 c, the first system-out NO_(x)sensor 164 a, the second system-out NO_(x) sensor 164 b, the thirdsystem-out NO_(x) sensor 164 c, the first engine-out NO_(x) sensor 450a, the second engine-out NO_(x) sensor 450 b, the third engine-outNO_(x) sensor 450 c, the first particulate sensor 460 a, the secondparticulate sensor 460 b, the third particulate sensor 460 c, the firstNH₃ sensor 462 a, the second NH₃ sensor 462 b, the third NH₃ sensor 462c, the first system-out NO_(x) sensor 464 a, the second system-outNO_(x) sensor 464 b, or the third system-out NO_(x) sensor 464 c. Theserial process 700 can be implemented with the first exhaust gasaftertreatment sensor system 157 or the second exhaust gasaftertreatment sensor system 457.

The serial process 700 starts in block 702 with utilizing (e.g.,selecting, using, etc.), by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, the first sensor 202 as theprimary sensor. The exhaust gas aftertreatment system controller 132 orthe controller 432 can utilize the second sensor 204 as a secondarysensor or supporting sensor. During the serial process 700, the primarysensor and the secondary sensor are both measuring a parameter (e.g.,the same parameter) of the exhaust gas flowing through the exhaust gasaftertreatment system 102 or the exhaust gas aftertreatment system 102.The parameter can be a gas (e.g., NO_(x), NH₃, O₂, etc.) concentration,engine-out NO_(x) concentration, system-out NO_(x) concentration,particulate matter concentration, particulate number, or pressure) inthe exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402. The exhaust gas aftertreatment systemcontroller 132 or the controller 432 uses the sensor values from theprimary sensor to control operation of the exhaust gas aftertreatmentsystem 102 or the exhaust gas aftertreatment system 402. The exhaust gasaftertreatment system controller 132 or the controller 432 uses thesensor values from the secondary sensor to check if the primary sensorhas failed. The primary sensor, the first sensor 202, operates untilfailure, at which point, a supporting sensor (e.g., secondary sensor,tertiary sensor), the second sensor 204, assumes the role of the primarysensor. Failure of the primary sensor, the first sensor 202, may occurwhen, for example, the first sensor 202 accumulates debris, dirt ordust, becomes contaminated by chemicals that leak into the exhaust gasaftertreatment system 102, the heater fails, or the sensor cracks.

The serial process 700 then progresses through a sensor check process703 (e.g., method, procedure, etc.). The sensor check process 703 startsin block 704 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, if a current state is less than atarget state. The current state can include a start state of 0 (e.g. 0miles, 0 hours, etc.). The current state can change upon operation ofthe internal combustion engine 108 as the vehicle system increasesmileage or operates for a period of time. The target state can include anumber of miles (e.g., 1,000 miles, 5,000 miles, 10,000 miles, etc.) ora number of hours (e.g., 100 hours, 1000 hours, 2000 hours, etc.). Ifthe exhaust gas aftertreatment system controller 132 or the controller432 determines that the current state is less than the target state,then the sensor check process 703 ends and the serial process 700continues to block 702 (e.g., is re-run, etc.).

If the exhaust gas aftertreatment system controller 132 or thecontroller 432 determines that the current state is greater than orequal to the target state, then the sensor check process 703 continuesin block 705 with resetting, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, the current state to the startstate.

The sensor check process 703 continues in block 706 with receiving, bythe exhaust gas aftertreatment system controller 132 or the controller432, a first sensor value (V_(first sensor)) from the first sensor 202.At target intervals, the exhaust gas aftertreatment system controller132 or the controller 432 can receive the V_(first sensor) from thefirst sensor 202. The target interval can be the difference between thetarget state and the start state. The target interval can be an amountof time (e.g., 100 hours, 1000 hours, 2000 hours, etc.) set by theexhaust gas aftertreatment system controller 132 or the controller 432.The target interval can be a number of miles (e.g., 1,000 miles, 5,000miles, 10,000 miles, etc.) set by the exhaust gas aftertreatment systemcontroller 132 or the controller 432. For example, the V_(first sensor)may be equal to a parameter (e.g., a gas (e.g., NO_(x), NH₃, O₂, etc.)concentration, engine-out NO_(x) concentration, system-out NO_(x)concentration, particulate matter concentration, particulate number, orpressure) received by the first sensor 202.

The sensor check process 703 continues in block 708 with receiving, bythe exhaust gas aftertreatment system controller 132 or the controller432, a second sensor value (V_(second sensor)) from the second sensor204. The second sensor 204 can measure the same parameter as the firstsensor 202. At target intervals, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 can receive the V_(second sensor)from the second sensor 204. For example, the V_(second sensor) may beequal to a parameter (e.g., a gas (e.g., NO_(x), NH₃, O₂, etc.)concentration, engine-out NO_(x) concentration, system-out NO_(x)concentration particulate matter concentration, particulate number, orpressure) received by the first sensor 202.

The sensor check process 703 continues in block 710 with calculating, bythe exhaust gas aftertreatment system controller 132, a differencebetween the V_(first sensor) and the V_(second sensor). For example, thedifference between the V_(first sensor) and the V_(second sensor) can bethe V_(first sensor) subtracted from the V_(second sensor). Thedifference between the V_(first sensor) and the V_(second sensor) can bethe V_(second sensor) subtracted from the V_(first sensor).

The sensor check process 703 continues in block 712 with determining, bythe exhaust gas aftertreatment system controller 132 or the controller432, if the difference between the V_(first sensor) and theV_(second sensor) is greater than a threshold value (V_(threshold)). Forexample, the difference between the V_(first sensor) and theV_(second sensor) can be less than the V_(threshold), equal to theV_(threshold), or greater than the V_(threshold). In some embodiments,block 712 may be represented by

V _(first sensor) −V _(second sensor) >V _(threshold)   (1)

If the difference between the V_(first sensor) and the V_(second sensor)is less than or equal to the V_(threshold) (e.g., if Equation (1) is nottrue, etc.), the exhaust gas aftertreatment system controller 132 or thecontroller 432 can continue utilizing the first sensor 202 as theprimary sensor.

If the exhaust gas aftertreatment system controller 132 or thecontroller 432 determines that the difference between theV_(first sensor) and the V_(second sensor) is greater than theV_(threshold) (e.g., if Equation 1 is true, etc.), then the sensor checkprocess 703 continues in block 714 with utilizing, by the exhaust gasaftertreatment system controller 132 or the controller 432, the secondsensor 204 as the primary sensor for measuring the parameter in theexhaust gas aftertreatment system 102.

In some embodiments, the serial process 700 can be utilized in theexhaust gas aftertreatment system 102 or the exhaust gas aftertreatmentsystem 402 including a third sensor 206. The serial process 700 isdescribed with reference to the third sensor 206. It is understood thatthe third sensor 206 is any of the first engine-out NO_(x) sensor 150 a,the second engine-out NO_(x) sensor 150 b, the third engine-out NO_(x)sensor 150 c, the first particulate sensor 160 a, the second particulatesensor 160 b, the third particulate sensor 160 c, the first NH₃ sensor162 a, the second NH₃ sensor 162 b, the third NH₃ sensor 162 c, thefirst system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, the third system-out NO_(x) sensor 164 c, the firstengine-out NO_(x) sensor 450 a, the second engine-out NO_(x) sensor 450b, the third engine-out NO_(x) sensor 450 c, the first particulatesensor 460 a, the second particulate sensor 460 b, the third particulatesensor 460 c, the first NH₃ sensor 462 a, the second NH₃ sensor 462 b,the third NH₃ sensor 462 c, the first system-out NO_(x) sensor 464 a,the second system-out NO_(x) sensor 464 b, or the third system-outNO_(x) sensor 464 c.

The exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402 includes a third sensor 206 disposed proximatethe first sensor 202 and the second sensor 204 and configured to measurethe parameter in the exhaust gas aftertreatment system 102. The exhaustgas aftertreatment system controller 132 or the controller 432 canreceive a third sensor value from the third sensor. The exhaust gasaftertreatment system controller 132 or the controller 432 can calculatea difference between the V_(second sensor) and the third sensor value.The exhaust gas aftertreatment system controller 132 or the controller432 can determine if the difference between the V_(second sensor) andthe third sensor value is greater than the V_(threshold). If thedifference between the V_(second sensor) and the third sensor value isgreater than the V_(threshold), the exhaust gas aftertreatment systemcontroller 132 or the controller 432 can stop utilizing the secondsensor 204 as the primary sensor for measuring the parameter in exhaustgas aftertreatment system and begin utilizing the third sensor as theprimary sensor for measuring the parameter in exhaust gas aftertreatmentsystem.

In some embodiments, the V_(threshold) is calculated based onaftertreatment operating conditions. For example, the exhaust gasaftertreatment system controller 132 or the controller 432 calculatesthe V_(threshold) based on at least one aftertreatment operatingcondition and/or at least one engine operating condition. An engineoperating condition can include exhaust temperatures (e.g., dew pointtemperature) or an idle condition. For example, the dew pointtemperature can include a temperature above which the sensor will turnon and below which the sensor will turn off. In some embodiments, thefirst sensor 202 includes at least one of a multiple gas sensor, aparticulate matter sensor, a particulate number sensor, or a deltapressure sensor. In some embodiments, the first sensor 202 includes aplurality of sensing elements. In some embodiments, the first sensor 202includes a first filter and the second sensor 204 includes a secondfilter.

In some embodiments, the serial process 700 includes determining adifference between the V_(first sensor) and a calculated sensor value,the calculated sensor value based on at least one aftertreatmentoperating condition and/or at least one engine operating condition. Forexample, the exhaust gas aftertreatment system controller 132 or thecontroller 432 can determine a difference between the V_(first sensor)and a calculated sensor value. The exhaust gas aftertreatment systemcontroller 132 or the controller 432 can determine a difference betweenthe V_(second sensor) and the calculated sensor value. If the differencebetween the V_(first sensor) and the calculated sensor value is lessthan or equal to the difference between the V_(second sensor) and thecalculated sensor value, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 can utilize the first sensor as theprimary sensor for measuring the parameter in exhaust gas aftertreatmentsystem. If the difference between the V_(first sensor) and thecalculated sensor value is greater than the difference between theV_(second sensor) and the calculated sensor value, the exhaust gasaftertreatment system controller 132 or the controller 432 can utilizethe second sensor as the primary sensor for measuring the parameter inexhaust gas aftertreatment system.

The controller 132 or the controller 432 can contain logic to limitoperation in a comparison mode (e.g., instantaneous comparison mode,time averaged comparison mode, etc.) during certain engine operatingconditions (e.g., exhaust temperature, idle condition, etc.). Forexample, the comparison mode may operate at an exhaust temperature above200° C. and may not operate (e.g., be disabled) at exhaust temperaturesat or below 200° C. The controller 132 or the controller 432 can averagesensor values from the first sensor 202 and the second sensor 204. Thecontroller 132 or the controller 432 can average sensor values from thefirst sensor 202 and sensor values from the second sensor 204 on asecond by second basis, a time-averaged basis (e.g., 30 second movingaverage, 60 second moving average, etc.), or a time-weighted averagebasis. For example, using the moving average can suppress an error dueto a cold start whereby a sensor provides an inaccurate or bad readingduring the cold start but is otherwise fully operational.

VII. Example Alternating Selection Process for an Exhaust GasAftertreatment System

FIG. 8 is a flow chart of an alternating selection process 800 (e.g.,method, procedure, etc.) for controlling operation of one or moresensors in the exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402. The alternating selection process 800 isdescribed with reference to the first sensor 202 and the second sensor204. It is understood that the first sensor 202 is any of the firstengine-out NO_(x) sensor 150 a, the second engine-out NO_(x) sensor 150b, the third engine-out NO_(x) sensor 150 c, the first particulatesensor 160 a, the second particulate sensor 160 b, the third particulatesensor 160 c, the first NH₃ sensor 162 a, the second NH₃ sensor 162 b,the third NH₃ sensor 162 c, the first system-out NO_(x) sensor 164 a,the second system-out NO_(x) sensor 164 b, the third system-out NO_(x)sensor 164 c, the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, the third engine-out NO_(x) sensor 450c, the first particulate sensor 460 a, the second particulate sensor 460b, the third particulate sensor 460 c, the first NH₃ sensor 462 a, thesecond NH₃ sensor 462 b, the third NH₃ sensor 462 c, the firstsystem-out NO_(x) sensor 464 a, the second system-out NO_(x) sensor 464b, or the third system-out NO_(x) sensor 464 c.

Similarly, it is understood that the second sensor 204 is any of thefirst engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, the third engine-out NO_(x) sensor 150 c, the firstparticulate sensor 160 a, the second particulate sensor 160 b, the thirdparticulate sensor 160 c, the first NH₃ sensor 162 a, the second NH₃sensor 162 b, the third NH₃ sensor 162 c, the first system-out NO_(x)sensor 164 a, the second system-out NO_(x) sensor 164 b, the thirdsystem-out NO_(x) sensor 164 c, the first engine-out NO_(x) sensor 450a, the second engine-out NO_(x) sensor 450 b, the third engine-outNO_(x) sensor 450 c, the first particulate sensor 460 a, the secondparticulate sensor 460 b, the third particulate sensor 460 c, the firstNH₃ sensor 462 a, the second NH₃ sensor 462 b, the third NH₃ sensor 462c, the first system-out NO_(x) sensor 464 a, the second system-outNO_(x) sensor 464 b, or the third system-out NO_(x) sensor 464 c. Thealternating selection process 800 can be implemented with the firstexhaust gas aftertreatment sensor system 157 or the second exhaust gasaftertreatment sensor system 457.

The alternating selection process 800 starts in block 802 withalternately receiving (e.g., acquiring, accepting, collecting,gathering, etc.), by the exhaust gas aftertreatment system controller132 or the controller 432, sensor values from the first sensor 202 for afirst target period of time and receiving (e.g., acquiring, accepting,collecting, gathering, etc.), by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, sensor values from the secondsensor 204 for a second target period of time. The first target periodof time and the second target period of time can be a range of times(e.g., between 0 and 100 hours, between 100 and 150 hours, etc.).Alternately is intended to mean that the exhaust gas aftertreatmentsystem controller 132 or the controller 432 receives sensor values fromthe first sensor 202 followed by the sensor values from the secondsensor 204 in an alternating fashion. For example, the first sensor 202and the second sensor 204 operate an equal fraction of time, switchingat a defined time interval (e.g., every 100 hours, every 1000 hours,etc.). The exhaust gas aftertreatment system controller 132 or thecontroller 432 can receive sensor values from the first sensor 202 forthe first target period of time of between 0 and 100 hours. Between 0and 100 hours, the exhaust gas aftertreatment system controller 132 orthe controller 432 does not receive sensor values from the second sensor204. The exhaust gas aftertreatment system controller 132 or thecontroller 432 can receive sensor values from the second sensor 204 forthe second target period of time between 100 hours and 200 hours.Between 100 hours and 200 hours, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 does not receive sensor values fromthe first sensor 202. The exhaust gas aftertreatment system controller132 or the controller 432 can receive sensor values from the firstsensor 202 for the first target period of time between 200 and 300hours. Between 200 and 300 hours, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 does not receive sensor values fromthe second sensor 204. The exhaust gas aftertreatment system controller132 or the controller 432 can receive sensor values from the secondsensor 204 for the second target period of time between 300 hours and400 hours. Between 300 hours and 400 hours, the exhaust gasaftertreatment system controller 132 or the controller 432 does notreceive sensor values from the first sensor 202. In the manner describedabove, the exhaust gas aftertreatment system controller 132 or thecontroller 432 alternately receives sensor values from the first sensor202 for the first target period of time beginning every 200 hours for100 hours each time and receives sensor values from the second sensor204 for the second target period of time beginning every 200 hours for100 hours each time.

In another example, the first sensor 202 and the second sensor 204operate an unequal fraction of time, switching at a defined timeinterval. The exhaust gas aftertreatment system controller 132 or thecontroller 432 can receive sensor values from the first sensor 202 forthe first target period of time between 0 and 100 hours. Between 0 and100 hours, the exhaust gas aftertreatment system controller 132 or thecontroller 432 does not receive sensor values from the second sensor204. The exhaust gas aftertreatment system controller 132 or thecontroller 432 can receive sensor values from the second sensor 204 forthe second target period of time between 100 hours and 150 hours.Between 100 hours and 150 hours, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 does not receive sensor values fromthe first sensor 202. The exhaust gas aftertreatment system controller132 or the controller 432 can receive sensor values from the firstsensor 202 for the first target period of time between 150 and 250hours. Between 150 and 250 hours, the exhaust gas aftertreatment systemcontroller 132 or the controller 432 does not receive sensor values fromthe second sensor 204. The exhaust gas aftertreatment system controller132 or the controller 432 can receive sensor values from the secondsensor 204 for the second target period of time between 250 hours and300 hours. Between 250 hours and 300 hours, the exhaust gasaftertreatment system controller 132 or the controller 432 does notreceive sensor values from the first sensor 202. In the manner describedabove, the exhaust gas aftertreatment system controller 132 or thecontroller 432 alternately receives sensor values from the first sensor202 for the first target period of time beginning every 150 hours for100 hours each time and receives sensor values from the second sensor204 for the second target period of time beginning every 150 hours for50 hours each time.

In some embodiments, the alternating selection process 800 continues inblock 804 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, a difference between a Vast sensorreceived from the first sensor and a calculated sensor value(V_(calculated)). The V_(calculated) can be based on at least oneaftertreatment operating condition and/or at least one engine operatingcondition.

In some embodiments, the alternating selection process 800 continues inblock 806 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, a difference between aV_(second sensor) received from the second sensor and theV_(calculated). The V_(calculated) can be based on at least oneaftertreatment operating condition and/or at least one engine operatingcondition. The difference between the V_(second sensor) received fromthe second sensor and the V_(calculated) can be based on instantaneoussensor readings (e.g., instantaneous V_(second sensor) readings) or timeaveraged readings (e.g., time averaged V_(second sensor) readings).

The controller 132 or the controller 432 can contain logic to limitoperation in a comparison mode (e.g., instantaneous comparison mode,time averaged comparison mode, etc.) during certain engine operatingconditions (e.g., exhaust temperature, idle condition, etc.). Forexample, the comparison mode may operate at an exhaust temperature above200° C. and may not operate (e.g., be disabled) at exhaust temperaturesat or below 200° C. The controller 132 or the controller 432 can averagesensor values from the first sensor 202 and the second sensor 204. Thecontroller 132 or the controller 432 can average sensor values from thefirst sensor 202 and sensor values from the second sensor 204 on asecond by second basis, a time-averaged basis (e.g., 30 second movingaverage, 60 second moving average, etc.), or a time-weighted averagebasis. For example, using the moving average can suppress an error dueto a cold start whereby a sensor provides an inaccurate or bad readingduring the cold start but is otherwise fully operational.

In some embodiments, the alternating selection process 800 continues inblock 808 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, if the difference between theV_(first sensor) and the V_(calculated) is greater than or equal to aV_(threshold). For example, the difference between the V_(first sensor)and the V_(calculated) can be less than the V_(threshold), equal to theV_(threshold), or greater than the V_(threshold). In some embodiments,block 808 may be represented by

V _(first sensor) −V _(calculated) ≥V _(threshold)   (2)

If the difference between the V_(first sensor) and the V_(calculated) isgreater than or equal to the V_(threshold) (e.g., if Equation (2) istrue, etc.), the alternating selection process 800 continues in block810 with deactivating, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, the first sensor 202 and receivingsensor values only from the second sensor 204.

If the difference between the V_(first sensor) and the V_(calculated) isless than the V_(threshold) (e.g., if Equation (2) is not true, etc.),the exhaust gas aftertreatment system controller 132 or the controller432 continues in block 812 determining, by the exhaust gasaftertreatment system controller 132 or the controller 432, if thedifference between the V_(second sensor) and the V_(calculated) isgreater than or equal to the V_(threshold). For example, the differencebetween the V_(second sensor) and the V_(calculated) can be less thanthe V_(threshold), equal to the V_(threshold), or greater than theV_(threshold). In some embodiments, block 812 may be represented by

V _(second sensor) −V _(calculated) ≥V _(threshold)   (3)

If the difference between the V_(second sensor) and the V_(calculated)is greater than or equal to the V_(threshold) (e.g., if Equation (3) istrue, etc.), the alternating selection process 800 continues in block814 with deactivating, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432 the second sensor 204 and receivingsensor values only from the first sensor 202.

If the difference between the V_(second sensor) and the V_(calculated)is less than the threshold (e.g., if Equation (3) is not true, etc.),the alternating selection process 800 continues to block 802 (e.g., isre-run, etc.).

In some embodiments, the alternating selection process 800 can beutilized in the exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402 including a third sensor 206. The alternatingselection process 800 is described with reference to the third sensor206. It is understood that the third sensor 206 is any of the firstengine-out NO_(x) sensor 150 a, the second engine-out NO_(x) sensor 150b, the third engine-out NO_(x) sensor 150 c, the first particulatesensor 160 a, the second particulate sensor 160 b, the third particulatesensor 160 c, the first NH₃ sensor 162 a, the second NH₃ sensor 162 b,the third NH₃ sensor 162 c, the first system-out NO_(x) sensor 164 a,the second system-out NO_(x) sensor 164 b, the third system-out NO_(x)sensor 164 c, the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, the third engine-out NO_(x) sensor 450c, the first particulate sensor 460 a, the second particulate sensor 460b, the third particulate sensor 460 c, the first NH₃ sensor 462 a, thesecond NH₃ sensor 462 b, the third NH₃ sensor 462 c, the firstsystem-out NO_(x) sensor 464 a, the second system-out NO_(x) sensor 464b, or the third system-out NO_(x) sensor 464 c.

The exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402 includes a third sensor 206 disposed proximatethe first sensor 202 and the second sensor 204 and configured to measurethe parameter in the exhaust gas aftertreatment system 102. The exhaustgas aftertreatment system controller 132 or the controller 432 canalternately receive a third sensor value from the third sensor for athird target period of time. The third target period of time can be arange of times (e.g., between 0 and 100 hours, between 100 and 150hours, etc.). The exhaust gas aftertreatment system controller 132 orthe controller 432 can determine a difference between a third sensorvalue received from the third sensor and the V_(calculated). If thedifference between the third sensor value and the V_(calculated) isgreater than or equal to the V_(threshold), the exhaust gasaftertreatment system controller 132 or the controller 432 candeactivate the third sensor 206 and receive sensor values only from thesecond sensor 204. If the difference between the V_(second sensor) andthe V_(calculated) is greater than or equal to the V_(threshold), theexhaust gas aftertreatment system controller 132 or the controller 432can deactivate the second sensor 204 and receive sensor values only fromthe third sensor 206.

In some embodiments, the first sensor 202 includes at least one of amultiple gas sensor, a particulate matter sensor, a particulate numbersensor, or a delta pressure sensor. In some embodiments, the firstsensor 202 includes a plurality of sensing elements. In someembodiments, the first sensor 202 includes a first filter and the secondsensor 204 includes a second filter.

VIII. Example Simultaneous Selection Process for an Exhaust GasAftertreatment System

FIG. 9 is a flow chart of a simultaneous selection process 900 (e.g.,method, procedure, etc.) for controlling operation of one or moresensors in the exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402. The simultaneous selection process 900 cangenerate an average sensor value based on multiple sensors, therebyproviding a more accurate concentration in comparison to a single sensorvalue. The average sensor value can also facilitate the detection of afailing or failed sensor based on sensor values of multiple sensors. Thesimultaneous selection process 900 is described with reference to thefirst sensor 202 and the second sensor 204. It is understood that thefirst sensor 202 is any of the first engine-out NO_(x) sensor 150 a, thesecond engine-out NO_(x) sensor 150 b, the third engine-out NO_(x)sensor 150 c, the first particulate sensor 160 a, the second particulatesensor 160 b, the third particulate sensor 160 c, the first NH₃ sensor162 a, the second NH₃ sensor 162 b, the third NH₃ sensor 162 c, thefirst system-out NO_(x) sensor 164 a, the second system-out NO_(x)sensor 164 b, the third system-out NO_(x) sensor 164 c, the firstengine-out NO_(x) sensor 450 a, the second engine-out NO_(x) sensor 450b, the third engine-out NO_(x) sensor 450 c, the first particulatesensor 460 a, the second particulate sensor 460 b, the third particulatesensor 460 c, the first NH₃ sensor 462 a, the second NH₃ sensor 462 b,the third NH₃ sensor 462 c, the first system-out NO_(x) sensor 464 a,the second system-out NO_(x) sensor 464 b, or the third system-outNO_(x) sensor 464 c.

Similarly, it is understood that the second sensor 204 is any of thefirst engine-out NO_(x) sensor 150 a, the second engine-out NO_(x)sensor 150 b, the third engine-out NO_(x) sensor 150 c, the firstparticulate sensor 160 a, the second particulate sensor 160 b, the thirdparticulate sensor 160 c, the first NH₃ sensor 162 a, the second NH₃sensor 162 b, the third NH₃ sensor 162 c, the first system-out NO_(x)sensor 164 a, the second system-out NO_(x) sensor 164 b, the thirdsystem-out NO_(x) sensor 164 c, the first engine-out NO_(x) sensor 450a, the second engine-out NO_(x) sensor 450 b, the third engine-outNO_(x) sensor 450 c, the first particulate sensor 460 a, the secondparticulate sensor 460 b, the third particulate sensor 460 c, the firstNH₃ sensor 462 a, the second NH₃ sensor 462 b, the third NH₃ sensor 462c, the first system-out NO_(x) sensor 464 a, the second system-outNO_(x) sensor 464 b, or the third system-out NO_(x) sensor 464 c. Thesimultaneous selection process 900 can be implemented with the firstexhaust gas aftertreatment sensor system 157 or the second exhaust gasaftertreatment sensor system 457.

The simultaneous selection process 900 starts in block 902 withsimultaneously receiving (e.g., acquiring, accepting, collecting,gathering, etc.), by the exhaust gas aftertreatment system controller132 or the controller 432, sensor values from the first sensor 202 andreceiving (e.g., acquiring, accepting, collecting, gathering, etc.), bythe exhaust gas aftertreatment system controller 132 or the controller432, sensor values from the second sensor 204. The sensor values fromthe first sensor 202 and the sensor values from the second sensor 204can be averaged by the exhaust gas aftertreatment system controller 132or the controller 432 to provide a more accurate concentration incomparison to sensor values from either the first sensor 202 or secondsensor 204 alone. The exhaust gas aftertreatment system controller 132or the controller 432 can average sensor values from the first sensor202 and sensor values from the second sensor 204 on a second by secondbasis or a time-averaged basis (e.g., 30 second moving average, 60second moving average, etc.).

The controller 132 or the controller 432 can contain logic to limitoperation in a comparison mode (e.g., instantaneous comparison mode,time averaged comparison mode, etc.) during certain engine operatingconditions (e.g., exhaust temperature, idle condition, etc.). Forexample, the comparison mode may operate at an exhaust temperature above200° C. and may not operate (e.g., be disabled) at exhaust temperaturesat or below 200° C. The controller 132 or the controller 432 can averagesensor values from the first sensor 202 and the second sensor 204. Thecontroller 132 or the controller 432 can average sensor values from thefirst sensor 202 and sensor values from the second sensor 204 on asecond by second basis, a time-averaged basis (e.g., 30 second movingaverage, 60 second moving average, etc.), or a time-weighted averagebasis. For example, using the moving average can suppress an error dueto a cold start whereby a sensor provides an inaccurate or bad readingduring the cold start but is otherwise fully operational.

In some embodiments, the simultaneous selection process 900 continues inblock 904 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, a difference between aV_(first sensor) received from the first sensor 202 and aV_(second sensor) received from the second sensor 204.

In some embodiments, the simultaneous selection process 900 continues inblock 906 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, if the difference between theV_(first sensor) received from the first sensor 202 and theV_(second sensor) received from the second sensor 204 is greater than orequal to a first threshold value (V_(first threshold)). For example, thedifference between the V_(first sensor) received from the first sensor202 and the V_(second sensor) received from the second sensor 204 can beless than the V_(first threshold), equal to the V_(first threshold), orgreater than the V_(first threshold). In some embodiments, block 906 maybe represented by

V _(first sensor) −V _(second sensor) ≥V _(first threshold)   (4)

If the difference between the V_(first sensor) received from the firstsensor 202 and the V_(second sensor) received from the second sensor 204is less than the V_(first threshold) (e.g., if Equation (4) is not true,etc.), the simultaneous selection process 900 continues to block 902(e.g., is re-run, etc.).

If the difference between the V_(first sensor) received from the firstsensor 202 and the V_(second sensor) received from the second sensor 204is greater than or equal to the V_(first threshold) (e.g., if Equation(4) is true, etc.), the simultaneous selection process 900 continues toblock 908 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, a difference between theV_(first sensor) and a V_(calculated). The V_(calculated) can be basedon at least one aftertreatment operating condition and/or at least oneengine operating condition. The difference between the V_(first sensor)and the V_(calculated) can be based on instantaneous sensor readings(e.g., instantaneous V_(first sensor) readings) or time averagedreadings (e.g., time averaged V_(first sensor) readings).

In some embodiments, the simultaneous selection process 900 continues inblock 910 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, a difference between theV_(second sensor) and the V_(calculated). The V_(calculated) can bebased on at least one aftertreatment operating condition and/or at leastone engine operating condition. The difference between theV_(second sensor) and the V_(calculated) can be based on instantaneoussensor readings (e.g., instantaneous V_(second sensor) readings) or timeaveraged readings (e.g., time averaged V_(second sensor) readings).

In some embodiments, the simultaneous selection process 900 continues inblock 912 with determining, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, if the difference between theV_(first sensor) and the V_(calculated) is greater than or equal to asecond threshold (V_(second threshold)). For example, the differencebetween the V_(first sensor) and the V_(calculated) can be less than theV_(second threshold), equal to the V_(second threshold), or greater thanthe V_(second threshold). In some embodiments, block 912 may berepresented by

V _(firstSensor) −V _(calculated) ≥V _(second threshold)   (5)

If the difference between the V_(first sensor) and the V_(calculated) isgreater than or equal to the V_(second threshold) (e.g., if Equation (5)is true, etc.), the simultaneous selection process 900 continues inblock 914 with deactivating, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432, the first sensor 202 and receivingsensor values only from the second sensor 204.

If the difference between the V_(first sensor) and the V_(calculated) isless than the V_(second threshold) (e.g., if Equation (5) is not true,etc.), the simultaneous selection process 900 continues in block 916determining, by the exhaust gas aftertreatment system controller 132 orthe controller 432, if the difference between the V_(second sensor) andthe V_(calculated) is greater than or equal to the V_(second threshold).For example, the difference between the V_(second sensor) and theV_(calculated) can be less than the V_(second threshold), equal to theV_(second threshold), or greater than the V_(second threshold). In someembodiments, block 916 may be represented by

V _(second sensor) −V _(calculated) ≥V _(second threshold)   (6)

If the difference between the V_(second sensor) and the V_(calculated)is greater than or equal to the V_(second threshold) (e.g., if Equation(6) is true, etc.), the simultaneous selection process 900 continues inblock 918 with deactivating, by the exhaust gas aftertreatment systemcontroller 132 or the controller 432 the second sensor 204 and receivingsensor values only from the first sensor 202.

If the difference between the V_(second sensor) and the V_(calculated)is less than the second threshold (e.g., if Equation (6) is not true,etc.), the simultaneous selection process 900 continues to block 902(e.g., is re-run, etc.).

In some embodiments, the simultaneous selection process 900 can beutilized in the exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402 including a third sensor 206. The simultaneousselection process 900 is described with reference to the third sensor206. It is understood that the third sensor 206 is any of the firstengine-out NO_(x) sensor 150 a, the second engine-out NO_(x) sensor 150b, the third engine-out NO_(x) sensor 150 c, the first particulatesensor 160 a, the second particulate sensor 160 b, the third particulatesensor 160 c, the first NH₃ sensor 162 a, the second NH₃ sensor 162 b,the third NH₃ sensor 162 c, the first system-out NO_(x) sensor 164 a,the second system-out NO_(x) sensor 164 b, the third system-out NO_(x)sensor 164 c, the first engine-out NO_(x) sensor 450 a, the secondengine-out NO_(x) sensor 450 b, the third engine-out NO_(x) sensor 450c, the first particulate sensor 460 a, the second particulate sensor 460b, the third particulate sensor 460 c, the first NH₃ sensor 462 a, thesecond NH₃ sensor 462 b, the third NH₃ sensor 462 c, the firstsystem-out NO_(x) sensor 464 a, the second system-out NO_(x) sensor 464b, or the third system-out NO_(x) sensor 464 c.

The exhaust gas aftertreatment system 102 or the exhaust gasaftertreatment system 402 includes a third sensor 206 disposed proximatethe first sensor 202 and the second sensor 204 and configured to measurethe parameter in the exhaust gas aftertreatment system 102. The exhaustgas aftertreatment system controller 132 or the controller 432 cansimultaneously receive (e.g., acquire, accept, collect, gather, etc.) athird sensor value from the third sensor. The exhaust gas aftertreatmentsystem controller 132 or the controller 432 can determine a differencebetween a third sensor value received from the third sensor and theV_(second sensor) received from the second sensor 204. If the differencebetween the V_(second sensor) and the third sensor value is greater thanor equal to the V_(first threshold), the exhaust gas aftertreatmentsystem controller 132 or the controller 432 can determine a differencebetween the third sensor value and the V_(calculated) based on at leastone aftertreatment operating condition and/or at least one engineoperating condition. If the difference between the third sensor valueand the V_(calculated) is greater than or equal to aV_(second threshold), the exhaust gas aftertreatment system controller132 or the controller 432 can deactivate the third sensor 206 andreceive sensor values only from the second sensor 204. If the differencebetween the second sensor value and the V_(calculated) is greater thanor equal to a V_(second threshold), the exhaust gas aftertreatmentsystem controller 132 or the controller 432 can deactivate the secondsensor 204 and receive sensor values only from the third sensor 206.

In some embodiments, the first sensor 202 includes at least one of amultiple gas sensor, a particulate matter sensor, a particulate numbersensor, or a delta pressure sensor. In some embodiments, the firstsensor 202 includes a plurality of sensing elements. In someembodiments, the first sensor 202 includes a first filter and the secondsensor includes a second filter.

IX. Construction of Example Embodiments

While this specification contains many specific implementation details,these should not be construed as limitations on the scope of what may beclaimed but rather as descriptions of features specific to particularimplementations. Certain features described in this specification in thecontext of separate implementations can also be implemented incombination in a single implementation. Conversely, various featuresdescribed in the context of a single implementation can also beimplemented in multiple implementations separately or in any suitablesub-combination. Moreover, although features may be described as actingin certain combinations and even initially claimed as such, one or morefeatures from a claimed combination can, in some cases, be excised fromthe combination, and the claimed combination may be directed to asub-combination or variation of a sub-combination.

As utilized herein, the terms “substantially” and similar terms areintended to have a broad meaning in harmony with the common and acceptedusage by those of ordinary skill in the art to which the subject matterof this disclosure pertains. It should be understood by those of skillin the art who review this disclosure that these terms are intended toallow a description of certain features described and claimed withoutrestricting the scope of these features to the precise numerical rangesprovided. Accordingly, these terms should be interpreted as indicatingthat insubstantial or inconsequential modifications or alterations ofthe subject matter described and claimed are considered to be within thescope of the invention as recited in the appended claims.

The terms “coupled,” “connected,” and the like, as used herein, mean thejoining of two components directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two components orthe two components and any additional intermediate components beingintegrally formed as a single unitary body with one another, with thetwo components, or with the two components and any additionalintermediate components being attached to one another.

The terms “fluidly coupled,” “in fluid communication,” and the like, asused herein, mean the two components or objects have a pathway formedbetween the two components or objects in which a fluid (e.g., exhaust,water, air, gaseous reductant, gaseous ammonia, etc.) may flow, eitherwith or without intervening components or objects. Examples of fluidcouplings or configurations for enabling fluid communication may includepiping, channels, or any other suitable components for enabling the flowof a fluid from one component or object to another.

It is important to note that the construction and arrangement of thesystem shown in the various example implementations is illustrative onlyand not restrictive in character. All changes and modifications thatcome within the spirit and/or scope of the described implementations aredesired to be protected. It should be understood that some features maynot be necessary, and implementations lacking the various features maybe contemplated as within the scope of the application, the scope beingdefined by the claims that follow. When the language “a portion” isused, the item can include a portion and/or the entire item, unlessspecifically stated to the contrary.

What is claimed is:
 1. An exhaust gas aftertreatment system comprising:a first sensor configured to measure a parameter in the exhaust gasaftertreatment system; a second sensor configured to measure theparameter in the exhaust gas aftertreatment system, the second sensordisposed proximate the first sensor; and at least one controllerconfigured to simultaneously receive sensor values from the first sensorand receive sensor values from the second sensor.
 2. The exhaust gasaftertreatment system of claim 1, wherein: the at least one controlleris configured to: determine a difference between a first sensor valuereceived from the first sensor and a second sensor value received fromthe second sensor, and if the difference between the first sensor valueand the second sensor value is greater than or equal to a firstthreshold value, determine a difference between the first sensor valueand a calculated sensor value based on at least one aftertreatmentoperating condition and/or at least one engine operating condition,determine a difference between the second sensor value and thecalculated sensor value based on the at least one aftertreatmentoperating condition and/or the at least one engine operating condition,if the difference between the first sensor value and the calculatedsensor value is greater than or equal to a second threshold value,deactivate the first sensor and receive sensor values only from thesecond sensor, and if the difference between the second sensor value andthe calculated sensor value is greater than or equal to the secondthreshold value, deactivate the second sensor and receive sensor valuesonly from the first sensor.
 3. The exhaust gas aftertreatment system ofclaim 2, further comprising: a third sensor disposed proximate the firstsensor and the second sensor and configured to measure the parameter inthe exhaust gas aftertreatment system; wherein the at least onecontroller is further configured to: simultaneously receive sensorvalues from the third sensor and receive sensor values from the secondsensor, determine a difference between a third sensor value receivedfrom the third sensor and the second sensor value received from thesecond sensor, if the difference between the second sensor value and thethird sensor value is greater than or equal to the first thresholdvalue, determine a difference between the third sensor value and thecalculated sensor value based on at least one aftertreatment operatingcondition and/or at least one engine operating condition, if thedifference between the third sensor value and the calculated sensorvalue is greater than or equal to a second threshold value, deactivatethe third sensor and receive sensor values only from the second sensor,and if the difference between the second sensor value and the calculatedsensor value is greater than or equal to the second threshold value,deactivate the second sensor and receive sensor values only from thethird sensor.
 4. The exhaust gas aftertreatment system of claim 1,wherein the first sensor includes at least one of a multiple gas sensor,a particulate matter sensor, a particulate number sensor, or a deltapressure sensor.
 5. The exhaust gas aftertreatment system of claim 1,wherein the first sensor includes a plurality of sensing elements. 6.The exhaust gas aftertreatment system of claim 1, wherein the firstsensor includes a first filter and the second sensor includes a secondfilter.
 7. The exhaust gas aftertreatment system of claim 1, wherein thefirst sensor comprises one or more sensing elements disposed on asubstrate.